Capsule type medical device system, and capsule type medical device

ABSTRACT

This capsule type medical device system includes: a position detection device  4  which detects the position within the living body of a capsule type medical device  2  which can be ingested to within the living body; an electrode  5  which is provided in the vicinity of the outer surface of the capsule type medical device  2 , and which applies an electrical stimulus to living body tissue; and a control device  6  which controls the electric current which flows to the electrode  5 ; and the control device  6  controls the electric current which flows to the electrode  5  based upon positional information which is detected by the position detection device  4.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a capsule type medical device systemwhich observes the inside of a living body, and in particular, whichshifts within the body while applying electrical stimuli to living bodytissues, and which is capable of observing a desired site.

The present application claims the priority of Japanese PatentApplication 2003-432674 filed upon Dec. 26, 2003, Japanese PatentApplication 2003-381202 filed upon Nov. 11, 2003, and Japanese PatentApplication 2003-431118 filed upon Dec. 25, 2003, and incorporates thecontents thereof herein by reference.

2. Description of Related Art

As methods by which a person who is to be investigated may check thestate of his own health, for example, from the past, there have beengenerally known methods for performing various types of checks by humanexamination or by endoscopy or the like. Furthermore, there is a knownmethod of investigation with a capsule type medical device, in which atesting module which is formed as a capsule is swallowed and is ingestedto within the living body, so that his state of health can easily bechecked. There have been various sorts of proposal for this kind ofcapsule type medical device, and, as one thereof, there is, for example,a known type of capsule type medical device of an electrically propelledtype, which shifts within the living body by applying a local electricalstimulus via an electrode to living body tissue, thus taking advantageof the shrinking action of such electrical stimulation upon living bodytissue (for example, refer to International Publication No. WO01/08548).

Normally, when such a capsule type medical device is ingested to withinthe living body, it shifts naturally along his alimentary canal due tothe peristaltic movement within, for example, his small intestine, bycontrast, by applying local electrical stimuli to the living bodytissue, this type of electrically propelled capsule type medical deviceis able, by performing shrinkage operation upon the living body tissuewhich is different from the peristaltic movement, to encourage itsshifting along the direction of progress, or to perform shifting in theopposite direction to the direction of progress. Therefore, it ispossible to perform observations with high efficiency, since it ispossible to perform detailed observation by arriving quickly at thedesired site for observation, and by lingering for some time at the sameposition.

SUMMARY OF THE INVENTION

The present invention proposes a capsule type medical device systemwhich includes a capsule type medical device which can be ingested to,within the living body, further including: a position detection devicewhich detects the position of the capsule type medical device within theliving body; an electrode which is provided in the vicinity of the outersurface of the capsule type medical device, and which applies anelectrical stimulus to living body tissue; and a control device whichcontrols the electric current which flows to the electrode; wherein thecontrol device controls the electric current which flows to theelectrode, based upon positional information which is detected by theposition detection device.

With the capsule type medical device system of the present invention, itis preferable that the capsule type medical device includes anacquisition device which acquires in-vivo information, and the positiondetection device decides upon the position of the capsule type medicaldevice within the living body, by using the in-vivo information which isacquired by the acquisition device.

With the capsule type medical device system of the present invention, itis preferable that the capsule type medical device system furtherincludes an external device which is disposed external to the livingbody, wherein a transmission section which transmits a physical quantityis provided to at least one or the other of the capsule type medicaldevice and the external device, a detection section which detects thephysical quantity which is transmitted from the transmission section isprovided to the other, and the position detection device detects theposition of the capsule type medical device within the living body, byusing the physical quantity which is detected by the detection section.

With the capsule type medical device system of the present invention, itis preferable that the capsule type medical device system furtherincludes an external device which is disposed outside the living body,wherein the capsule type medical device includes an internalacceleration sensor, the external device includes an externalacceleration sensor, and the position detection device detects theposition of the capsule type medical device within the living body,based upon the difference between the value detected by the internalacceleration sensor, and the value detected by the external accelerationsensor.

With the capsule type medical device system of the present invention, itis preferable that the position detection device includes a settingsection in which a necessary parameter until the capsule type medicaldevice arrives at a target site within the living body is set inadvance.

With the capsule type medical device system of the present invention, itis preferable that the capsule type medical device includes a balloonwhich can be expanded so as to closely contact to living body tissue, orcan be shrunk down, the electrode is provided upon the outer surface ofthe balloon, and the control device expands or shrinks down the balloon,based upon the positional information.

With the capsule type medical device system of the present invention, itis preferable that the electrode is provided in plurality, and thecontrol device controls the electric current which flows in theplurality of electrodes, based upon the positional information.

The present invention proposes a capsule type medical device, including:a capsule shaped casing which can be ingested to within the living body;an electrical stimulation device which includes a plurality ofelectrodes which are used for applying electrical stimuli to living bodytissue; an electrode selection device which selects an electrode fromamong the plurality of electrodes, to apply an electrical stimulus; acontact detection device which electrically detects the electrode whichis in contact with the living body tissue; and a control section whichcontrols the various devices.

With the capsule type medical device of the present invention, it ispreferable that the capsule type medical device further including: anacquisition device which acquires in-vivo information; and a storagedevice which stores the in-vivo information.

With the capsule type medical device of the present invention, it ispreferable that the electrical stimulation device includes: a waveformgenerator which generates a predetermined voltage waveform; a conversioncircuit which converts the voltage waveform to electric current; alimitation circuit which is used for adjusting the electric currentwhich flows to the electrode; and an electric current sensor whichdetects the electric current, the control section adjusts the gain ofthe limitation circuit according to the output of the electric currentsensor.

With the capsule type medical device of the present invention, it ispreferable that the contact detection device is a force detectiondevice.

With the capsule type medical device of the present invention, it ispreferable that the contact detection device measures the impedancebetween the electrode which is connected to the high electricalpotential side and the electrode which is connected to the lowelectrical potential side.

With the capsule type medical device of the present invention, it ispreferable that the capsule type medical device further includes asensor which detects shifting of the casing based upon the accelerationor the speed when the casing shifts.

The present invention proposes a capsule type medical device system,including: a capsule type medical device which can be ingested to withinthe living body; and an external device which is disposed external tothe living body; wherein the capsule type medical device includes: acapsule shaped casing; an acquisition device which acquires in-vivoinformation; a storage device which accumulates the in-vivo information;an internal communication device which transmits and receivesinformation with the external device; an electrical stimulation devicewhich includes a plurality of electrodes which are used for applyingelectrical stimulation to living body tissue; a contact detection devicewhich electrically detects that the electrodes are contacting the livingbody tissue, and which is used for selecting electrodes from theplurality of electrodes for applying electrical stimulation; and acontrol section which controls the various devices; the external deviceincludes: an external communication device which transmits and receivesinformation with the capsule type medical device; a recording devicewhich accumulates the in-vivo information; and an external controlsection which controls the various devices.

The present invention proposes a capsule type medical device, including:a capsule shaped casing; an imaging device which takes images of theinside of the living body; an electrical stimulation device which isprovided upon the outer surface of the casing, and which includes anelectrode which applies an electrical stimulus to living body tissue;and a control section which operates the imaging device and theelectrical stimulation device each at its own different timing.

The present invention proposes a capsule type medical device, including:a capsule shaped casing; an imaging device which takes images of theinside of the living body; an electrical stimulation device which areprovided upon the outer surface of one end and of the other end of thecasing with respect to its axial direction, and which includeselectrodes which apply an electrical stimulus to living body tissue; anda control section which operates the imaging device and the electricalstimulation device at the same time.

The present invention proposes a capsule type medical device, including:a capsule shaped casing; an imaging device which takes images of theinside of the living body; an electrical stimulation device which isprovided upon the outer surface of the casing and which includes anelectrode which applies an electrical stimulus to living body tissue;and a control section which operates the imaging device after apredetermined time period has elapsed, after having operated theelectrical stimulation device.

With the capsule type medical device system of the present invention, itis preferable that the capsule type medical device system furtherincluding: an acquisition device which acquires in-vivo information; anda storage device which stores the in-vivo information.

With the capsule type medical device system of the present invention, itis preferable that the capsule type medical device system furtherincluding: the electrical stimulation device which includes a pluralityof the electrodes; an electrode selection device which selects anelectrode from among the plurality of electrodes, to apply an electricalstimulus; a contact detection device which electrically detects that theelectrode is in contact with the living body tissue; and a controlsection which controls the various devices.

With the capsule type medical device system of the present invention, itis preferable that the electrical stimulation device includes: awaveform generator which generates a predetermined voltage waveform; aconversion circuit which converts the voltage waveform to electriccurrent; a limitation circuit which is used for adjusting the electriccurrent which flows to the electrode; and an electric current sensorwhich detects the electric current, the control section adjusts the gainof the limitation circuit according to the output of the electriccurrent sensor.

With the capsule type medical device system of the present invention, itis preferable that the position of the capsule type medical device isdetected by pattern recognition of the shift path of the capsule typemedical device which is acquired by the position detection device.

With the capsule type medical device system of the present invention, itis preferable that the capsule type medical device system furthercomprising an external device which is disposed externally to the livingbody, wherein the capsule type medical device includes an internal speedsensor, the external device includes an external speed sensor, and theposition detection device detects the position of the capsule typemedical device within the living body, based upon the difference betweenthe value detected by the internal speed sensor, and the value detectedby the external speed sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram showing a first embodiment of the capsuletype medical device system according to the present invention.

FIG. 2 is a sectional view showing a situation in which a balloon of thecapsule type medical device has been expanded.

FIG. 3 is a view showing a situation in which the capsule type medicaldevice is ingested into the living body, and electrical stimuli areapplied in correspondence to various sites.

FIG. 4 is a figure showing an example of the positioning of images whichhave been taken images by the capsule type medical device of thestomach, the small intestine, the colon, and the anus.

FIG. 5 is a figure showing a situation in which an electrical stimulusis being applied to living body tissue by the capsule type medicaldevice within the small intestine.

FIG. 6 is a sectional view showing a capsule type medical device whichincludes a pH sensor.

FIG. 7 is a figure showing an example of a position detection devicewhich detects the position of the capsule type medical device, by takingadvantage of radio wave strength.

FIG. 8 is a figure showing an example of a position detection devicewhich detects the position of the capsule type medical device, by takingadvantage of magnetic field strength.

FIG. 9 is a figure showing an example of a position detection devicewhich detects the position of the capsule type medical device, by takingadvantage of acceleration information.

FIG. 10 is a figure showing an example of a position detection devicewhich detects the position of the capsule type medical device, by takingadvantage of magnetic field.

FIG. 11 is a figure showing an example of a position detection devicewhich detects the position of the capsule type medical device, by takingadvantage of the shift pattern of the capsule type medical device.

FIG. 12 is a figure showing a situation in which an electrical stimulushas been applied for a brief period to living body tissue, in order todetect the orientation of the capsule type medical device.

FIG. 13 is a figure showing an example in which permanent magnets havebeen disposed outside the living body and within the capsule typemedical device, in order to regulate the orientation of the capsule typemedical device.

FIG. 14 is a figure showing a situation in which the capsule typemedical device is ingested to within the living body, in a state inwhich a string is detachably attached to it, in order to regulate theorientation of the capsule type medical device.

FIG. 15 is a simplified structural diagram showing a first variantexample of the first embodiment of the capsule type medical devicesystem according to the present invention.

FIG. 16 is a view showing the structure of a plus electrode portion anda minus electrode portion.

FIG. 17 is a view showing the structure of a sense of force sensor.

FIG. 18 is an external view of a capsule type medical device.

FIG. 19 is a view showing the external appearance of a rear portion ofthe capsule type medical device.

FIG. 20 is a sectional view of the rear portion of the capsule typemedical device.

FIG. 21 is a figure showing the change with time of a voltage waveformwhich is output from a gain adjustment circuit.

FIG. 22 is a figure showing the change with time of the voltage waveformwhich is output from the gain adjustment circuit.

FIG. 23 is a figure showing the change with time of the voltage waveformwhich is output from the gain adjustment circuit.

FIG. 24 is an external view showing a second variant example of thecapsule type medical device system according to the first embodiment ofthe present invention.

FIG. 25 is an external view showing a third variant example of thecapsule type medical device system according to the first embodiment ofthe present invention.

FIG. 26 is a structural diagram showing a fourth variant example of thecapsule type medical device system according to the first embodiment ofthe present invention.

FIG. 27 is a view showing the operational timing of a timing controllerof the capsule type medical device shown in FIG. 26.

FIG. 28 is a structural diagram showing a fifth variant example of thecapsule type medical device system according to the first embodiment ofthe present invention.

FIG. 29 is a structural diagram showing a sixth variant example of thecapsule type medical device system according to the first embodiment ofthe present invention.

FIG. 30 is an external view of the capsule type medical device shown inFIG. 29, and is a figure showing the positional relationship of theelectrodes.

FIG. 31 is a view showing a seventh variant example of the capsule typemedical device system according to the first embodiment of the presentinvention, and is a figure showing the operation timing of a timingcontroller.

FIG. 32 is a view showing a second embodiment of the capsule typemedical device system according to the present invention, and is afigure showing a situation in which the capsule type medical device hasbeen inserted into the colon via the anus, and is observing up to thecaecum.

FIG. 33 is a figure showing a situation in which, after the capsule typemedical device has been inserted into the colon via the anus, and hasshifted up to the caecum, it is observing within the colon whileshifting back to the anus again.

FIG. 34 is a sectional view showing an example of a capsule type medicaldevice of the present invention.

FIG. 35 is a sectional view showing another example of a capsule typemedical device of the present invention.

FIG. 36 is a sectional view showing yet another example of a capsuletype medical device of the present invention.

PREFERRED EMBODIMENTS FOR IMPLEMENTING THE INVENTION

In the following, the first embodiment of the capsule type medicaldevice system of the present invention will be explained with referenceto FIG. 1 through FIG 5.

As shown in FIG. 1, the capsule type medical device system 1 of thisembodiment includes a capsule type medical device 2 which can beingested to within the living body (to within a living body), anexternal device 3 which is disposed outside the living body, a positiondetection circuit (position detection device) 4 which detects theposition of the capsule type medical device 2 within the living body,electrodes 5 which are provided in the vicinity of the outer surface ofthe capsule type medical device 2 and which apply a stimulus to livingbody tissue, and a control section (a control device) 6 which controlsthe electric current which flows to the electrodes 5.

This capsule type medical device 2 includes: a capsule shaped casing 10;an acquisition device (an imaging device) 11 which acquires in-vivoinformation by taking images of the interior of his body; a wirelesstransmission and reception section (a transmission section, a detectionsection) 12 which, by generating and receiving radio waves (physicalquantities), send and receive information signals to and from theexternal device 3; a balloon 13 which can be expanded so as to closelycontact to living body tissue, and which can be shrunk; and a battery 14which supplies electrical power to these various structural elements.

The casing 10 is made from a plastic or the like so as to enclose itsinterior, and a transparent cover not shown in the figures is providedover one of its ends. An imaging element 20 which obtains an image bytaking images various parts of the inside of the living body, and anoptical system 21 such as a LED or the like which illuminates the visualrange of this imaging element 20 by irradiating it with illuminationlight are provided at the interior of this transparent cover. In otherwords, this imaging element 20 and optical system 21 constitute anacquisition device 11.

Furthermore, the above described balloon 13 is fitted around theperiphery of the casing 10, so as to enwrap the casing 10. This balloon13 is made from an elastic substance such as rubber or the like whichcan expand and contract, and, by an expansion and shrinkage mechanism 22which is provided within the casing 10, as for example shown in FIG. 2,it is possible to supply a flow of air or the like to within thisballoon 13 and thereby to expand it, or to shrink the balloon 13 bysucking out a mass of air from within the balloon 13. It should beunderstood that this expansion and shrinkage mechanism 22 is controlledby the control section 6. Furthermore, as shown in FIG. 1, when it hasbeen shrunk, the balloon 13 adheres closely to the outer surface of thecasing 10.

The electrodes 5 are provided upon the outer surface of the balloon 13.In other words, the electrodes 5 are positioned upon the outer surfaceof the casing 10 when the balloon 13 is shrunk down. Furthermore, theelectrodes 5 are provided in a plurality upon the outer surface of theballoon 13, so as to be respectively disposed at the one end thereof andat the other end thereof with respect to the axial direction of thecasing 10. It should be understood that, in this embodiment, electrodes5 at the one end are positioned at the side of the imaging element 20.Furthermore, the electrodes 5 can apply an electrical stimulus byflowing an electric current (an electrical signal) which has beensupplied from a current generation circuit 23 which is included in thecontrol section 6 into the living body tissue. At this time, the controlsection 6 controls the electric current which flows to each of theelectrodes 5 from the current generation circuit 23, based uponpositional information from the external device 3. This will beexplained in detail hereinafter.

The wireless transmission and reception section 12 includes atransmission and reception section main body which is not shown in thefigures, and a signal transmission and reception antenna (a transmissionantenna, a reception antenna) which transmits and receives radio wavesignals; and it is able to transmit the above described in-vivoinformation, in other words the images which have been taken images bythe imaging element 20, wirelessly to the external device 3.Furthermore, this wireless transmission and reception section 12receives control signals (information) which will be describedhereinafter which are transmitted wirelessly from the external device 3,and transmits them to the control section 6.

The control section 6 is equipped with the functions of, based upon thecontrol signals which it has received from the wireless transmission andreception section 12, supplying electric current to the electrodes 5from the current generation circuit 23, and stopping this supply ofelectric current to the electrodes 5 from the current generation circuit23. Furthermore, the control section 6 is equipped with the function ofcontrolling the expansion and shrinkage mechanism 22 based upon controlsignals, so as to operate the balloon 13 (i.e. to expand it or to shrinkit). This action of the control section 6 will be explained hereinafterin detail. It should be understood that the control section 6 isequipped with the function of controlling the various structuralelements described above in a combined manner.

As shown in FIG. 1, the external device 3 includes a main body 30, awireless transmission and reception section (a transmission section, adetection section) 31 which performs signal transmission and receipt ofinformation between itself and the capsule type medical device 2, arecording device 32 such as a memory or the like which accumulates theabove described in-vivo information, in other words images, a controlsection 33 which controls these various structural elements, and abattery 34 which supplies electrical power to these various structuralelements.

The main body 20 is made in the shape of a box from a metallic materialsuch as aluminum or the like, or a plastic material or the like, and canbe put on to his own body by the person who is the subject ofinvestigation via a belt or the like. Therefore, the main body 20 isalways arranged upon the outside of the body of the person who is thesubject of investigation.

The wireless transmission and reception section 31, in the same manneras the wireless transmission and reception section 12 of the capsuletype medical device 2, includes a transmission and reception sectionmain body not shown in the figures and a signal transmission andreception antenna (a transmission antenna, a reception antenna) whichtransmits and receives radio wave signals; and, along with beingequipped with the function of receiving the images, which are in-vivoinformation, which have been sent from the capsule type medical device 2and have arrived, it is also equipped with the function of sending themto the control section 33.

The control section 33, after having performed predetermined processingupon images such as image processing and the like, records them asrequired in the recording device 34. Furthermore, a position detectioncircuit 4 is provided to the control circuit 33. For example, an imagewhich is set in advance (a standard image) is set in this positiondetection circuit 4, and the position of the capsule type medical device2 within the living body is detected by comparing together this setimage and the image which has been sent and has arrived. It should beunderstood that, although this position detection circuit 4 detects theposition of the capsule type medical device 2 by comparing together theimage and the set image, this should not be considered to be limitative;it would also be acceptable to arrange to detect the position of thecapsule type medical device 2 based upon the characteristic amount of aspecific color in the image, or upon shapes or the like.

Furthermore, the control section 33 is equipped with the function ofsending a control signal to the capsule type medical device 2 via thewireless transmission and reception section 31, according to the sitewithin the living body (for example, the stomach, the small intestine,or the colon) at which it has been detected by the position detectioncircuit 4 that the capsule type medical device 2 is positioned.

It should be understood that, in this embodiment, the control section 33is set so as to transmit, respectively: a control signal to apply anelectrical stimulus, when the capsule type medical device 2 has arrivedat the small intestine; a control signal to cause the balloon 13 toexpand when it has arrived at the colon; and a control signal to causethe balloon 13 to shrink, along with stopping the electricalstimulation, when it has arrived at the anus. Moreover, it should beunderstood that the control signals which correspond to these siteswithin the living body are not limited to being the above describedones; it is possible to set them freely.

The case of observing the interior of the body of a person who is thesubject of investigation with the capsule type medical device system 1having the above described structure will now be explained.

First, as shown in FIG. 3, after having put on the external device 3 viaa belt or the like, the person who is the subject of investigationingests the capsule type medical device 2 via mouth. It should beunderstood that, at this time, a switch upon the capsule type medicaldevice 2 which is not shown is turned on, so that electrical power issupplied to the various structural components thereof from the battery14. By doing this, the control section 6 operates the acquisition device11, in other words the optical system 21 and the imaging element 20.

The capsule type medical device 2 which has been ingested to within theliving body, along with taking images various portions within the livingbody with the imaging element 20 while shifting along the alimentarycanal, also sends these images to the external device 3 by the wirelesstransmission and reception section 12. On the other hand, the externaldevice 3, along with receiving these images via the wirelesstransmission and reception section 31, also performs image processingand the like upon these images with the control section 33, and performsrecording of them in the recording device 32, as required.

Thus, as shown in FIG. 3, when the capsule type medical device 2 hasarrived at the stomach of the patient, the imaging element 20 sends animage of the stomach to the external device 3, as shown in FIG. 4. Bycomparison of the brightness or the color or the frequency distributionof the image, or the surface properties of the mucosa or the like, forthe image which has been sent and has arrived and for the set image, theposition detection circuit 4 of the external device 3 detects that thecapsule type medical device 2 is positioned at the stomach of thepatient. In this case, the control section 33 does not performtransmission of any control signal.

Next, as shown in FIG. 3, when the capsule type medical device 2 haspassed through the stomach and has arrived at the small intestine, theimaging element 20 sends images of the small intestine to the externaldevice 3, as shown in FIG. 4. The position detection circuit of theexternal device 3 detects that the capsule type medical device 2 ispositioned in the small intestine by comparing together the image whichhas been sent and the set image with regard to their brightness or coloror frequency distribution of the image, or the surface properties andcondition of the mucosa or the like. Upon receipt thereof, the controlsection 33 transmits a control signal for providing an electricalstimulus. At this time, the position detection circuit 4 detects theorientation of the capsule type medical device 2 from the image. Inother words, it detects the shifting direction due to the peristalticmovement of the small intestine from the change of the image. Forexample, the position detection circuit 4 may detect whether the imagingelement is oriented forwards or backwards, with respect to its directionof progress. That is, the position detection circuit 4 is able to decidewhether the electrodes 5 at the one end or at the other end arepositioned on the side of the direction of progress. Upon receipt of theresult thereof, the control section 33 transmits a control signal so asto apply an electrical stimulus from one or the other of theseelectrodes 5.

It should be understood that, in this embodiment, it is supposed thatthe imaging element 20 is positioned to the side of the direction ofprogress, in other words, that the electrodes 5 on the one end of thecapsule are positioned to the side of the direction of progress.

When the capsule type medical device 2 has arrived at the smallintestine, the wireless transmission and reception section 12 receives acontrol system which has been transmitted from the external device 3.Upon receipt of this control signal, the control section 6 supplies anelectric current with the current generation circuit 23 to theelectrodes 5 at the other end of the capsule, as shown in FIG. 5. Theseother end electrodes 5 to which this electric current has been suppliedapply an electrical stimulus to the living body tissue of the smallintestine (i.e. to the intestinal wall), and thereby shrink it. Byshrinking this living body tissue, the capsule type medical device 2proceeds along the direction of progress so as to shove aside the livingbody tissue. Accordingly, it is able to shift within the small intestinefaster than the speed of shifting due to the peristaltic movement of thesmall intestine, and it is able to perform observation within the smallintestine efficiently over a shortened time period.

Furthermore when, as shown in FIG. 3, the capsule has passed along thesmall intestine and has arrived at the colon, the imaging element 20transmits images of the colon to the external device 3, as shown in FIG.4. In the same manner as described above, the position detection circuit4 of the external device 3 detects the fact that the capsule typemedical device 2 has arrived at the colon from these images, and thecontrol section 33 sends a control signal corresponding to the colon tothe capsule type medical device 2. In other words, along with applyingan electrical stimulus from the electrodes 5 at the other end of thecapsule, the control section 33 also transmits a control signal bywireless so as to cause the balloon 13 to expand. Upon receipt thereof,as shown in FIG. 2 and FIG. 3, in the capsule type medical device 2, thecontrol section 6 operates the expansion and shrinkage mechanism 22 soas to cause the balloon 13 to expand. By doing this, it is possible toapply an electrical stimulus in the state in which the electrodes 5 arepressed closely and in a reliable manner against the living body tissueof the colon (the intestinal wall) which is comparatively large in size,as compared to the small intestine, so that, in the same way as for thesmall intestine, it is possible to shorten the time period required forperforming the examination efficiently, and moreover while driving thecapsule in a stabilized manner.

As shown in FIG. 3, when the capsule has passed through the colon andhas arrived at the anus, the imaging element 20 transmits an image ofthe anus to the external device 3, as shown in FIG. 4. In the samemanner as described above, the position detection circuit 4 of theexternal device 3 detects the fact that the capsule type medical device2 has arrived at the anus from this image, and the control section 33transmits a control signal corresponding to the anus to the capsule typemedical device 2. In other words, the control section 33 wirelesslysends a control signal which, along with shrinking down the balloon 13,also causes the electrical stimulation from the electrodes 5 on theother end of the capsule to be stopped. Upon receipt of this signal, asshown in FIG. 3, in the capsule type medical device 2, the controlsection 6 causes the expansion and shrinkage mechanism 22 to operate,and thus, by shrinking down the balloon 13, returns it to its originalstate. By doing this, the excretability of the capsule type medicaldevice 2 after the examination procedure has been completed is enhanced.

On the other hand, a doctor or the like performs diagnosis of the stateof health of the person who is the subject of investigation, based uponimages which are recorded in the recording device 32 of the externaldevice 3, which are in-vivo information.

According to the capsule type medical device system 1 described above,since it is possible to apply an electrical stimulus to living bodytissue which corresponds to a site within the living body, accordinglyit is possible to perform observation with good efficiency. Furthermore,it is possible to ensure stabilized operation while suppressing uselessconsumption of the energy in the battery 14. Since the electricalstimulation is not performed at a site such as, for example, the stomachor the like at which the effectiveness of electrical stimulation is low,accordingly it is possible to ensure that wasteful operation does notoccur. Furthermore, by providing the external device 3 which has acomplicated structure such as the position detection circuit 4 and thelike, it is possible to reduce the structure of the capsule type medicaldevice 2 to the minimum limit possible, and accordingly it is possibleto anticipate an enhancement in its compactness.

Yet further, since not only are images taken advantage of as in-vivoinformation, but also they are taken advantage of as positionaldetection information for the position detection circuit 4, accordinglyno structure is required for detecting separate information for thisposition detection. Accordingly, it is possible to anticipate asimplification of the structure of the device.

Even further, since the balloon 13 is provided, even in the case of asite which affords a comparatively wide space such as the colon, it ispossible to adhere the electrodes 5 securely against the living bodytissue and to apply an electrical stimulus thereby. Still further,since, along with arranging the electrodes 5 at the one end and at theother end of the capsule, also the control section 6 performs control ofthe electrical stimulation device 14 in correspondence to theorientation of the capsule type medical device 2 which has been detectedby the position detection circuit 4, accordingly it is possible toperform trustworthy control of the shift direction, irrespective of theattitude within the living body of the capsule endoscope 2.

It should be understood that although, in the above described firstembodiment, the capsule type medical device 2 included the balloon 13,this is not limitative; it would be acceptable for no such balloon 13 tobe incorporated. In such a case, it would be acceptable to affix theelectrodes 5 so that they are positioned upon the outer surface of thecasing 10.

Furthermore, although, as a position detection device for detecting theposition of the capsule type medical device 2 within the living body,the position detection circuit 4 is assembled to the control section 33of the external device 3, and the position of the capsule type medicaldevice 2 is detected based upon images, which are in-vivo information,which are captured by the imaging element 20, this is not to beconsidered as limitative. For example, it would also be acceptable, asshown in FIG. 6, for the acquisition device 11 of the capsule typemedical device 2 to include a pH sensor 40 which measures the pH valuewithin the living body, and for the position detection circuit 4 todetect the position of the capsule type medical device 2 based upon thepH value which is measured by this pH sensor 40. In this case, it wouldbe acceptable to arrange for it to be possible to perform mutualcommunication of the pH value (information) between the wirelesstransmission and reception section 12 of the capsule type medical device2 and the wireless transmission and reception section 31 of the externaldevice 3. By doing this, the position detection circuit 4 is able, forexample, to compare the pH value which has been measured with athreshold value which has been set in advance, or the like. Furthermore,the position detection circuit 4 is able to detect the position of thecapsule type medical device 2 within the living body based upon changesof the pH value which is measured (such as, for example, whether this pHvalue is the acidity within the stomach, or whether it has changed tothe neutrality in the small intestine), or the like. In particular, itis possible to anticipate a simplification of the algorithm used, ascompared with the positional detection according to images of the firstembodiment.

Yet further, it would also be acceptable to make the position detectiondevice so that it detected the position of the capsule type medicaldevice 2, based upon the strength of the radio waves which aretransmitted from the capsule type medical device 2. That is, as shown inFIG. 7, it would be acceptable to provide a structure in which thewireless transmission and reception section 12 of the capsule typemedical device 2 is made to be capable of generating wireless radiowaves, and in which the position detection device 45 included aplurality of reception antennas 46 which measured the radio wavestrength of the wireless radio waves which are provided to the externaldevice 3, so that the position of the capsule type medical device 2 isdetected based upon the strength of the radio waves which are receivedby these reception antennas 46. It should be understood that, in thiscase, the above described position detection device 45 includes thereception antennas 46 and the position detection circuit 4. Furthermore,it would also be acceptable to arrange the specified locations of thesereception antennas 46 so that they are positioned in the vicinity of,for example, the stomach, the small intestine, or the colon. By doingthis, it is possible for the position detection circuit 4 to detect thatthe capsule type medical device 2 has arrived at the small intestine,when the radio wave strength which is received by the reception antenna46 which is disposed in the vicinity of the small intestine reaches itshighest value. It is possible to perform positional detection for thecapsule type medical device 2 accurately by taking advantage of radiowave strength in this manner.

Furthermore, it would also be acceptable to make the position detectiondevice so that it detects the position of the capsule type medicaldevice 2 by taking advantage of magnetic field. In other words, as shownin FIG. 8, it would be acceptable to provide a structure in which theposition detection device 50 includes a magnetic field generation device51 not shown in the figure, such as a magnet or a coil or the like,provided to the capsule type medical device 2, which generates magneticfield, and a plurality of magnetic sensors, such as for example externalcoils (magnetic field detection device) 52, provided to the externaldevice 3, which measure magnetic field, so that the position of thecapsule type medical device 2 is detected based upon the magnetic fieldstrength which has been measured by each of these external coils 52. Inthis case, it would be acceptable to arrange to dispose each of theexternal coils 52 so that it is positioned at a specific site such as,for example, the vicinity of the stomach, of the small intestine, or ofthe colon. By doing this, if the magnetic field strength which ismeasured by the external coil 52 which is disposed in the vicinity ofthe small intestine is the highest, then it is possible to detect thatthe capsule type medical device 2 has arrived at the small intestine.Furthermore, it would also be acceptable for the magnetic fieldgeneration device 51 in the position detection device 50 to be a coilwhich generated an alternating magnetic field. In this case it wouldbecome possible, by taking advantage of this alternating magnetic field,to implement position detection by using a magnetic sensor, in the statein which the interference environment due to physical quantities or thelike which emanate from the environment is small. By taking advantage ofmagnetic field strength in this manner, it is possible to performpositional detection for the capsule type medical device 2 accurately.It should be understood that, apart from magnetic force, it would alsobe possible to perform the position detection in the same manner byusing some other physical quantity, such as electromagnetic waves, radiowaves, light, ultrasonic waves, or the like.

Furthermore, it would also be acceptable to make the position detectiondevice so that it detected the position of the capsule type medicaldevice 2 by taking advantage of acceleration information. In otherwords, as shown in FIG. 9, it would be acceptable for the positiondetection device 55 to include an acceleration sensor 56 internal to theliving body, provided to the capsule type medical device 2, which, alongwith measuring the acceleration within the living body, transmits thisacceleration information internal to the living body via the wirelesstransmission and reception section 12, and an acceleration sensor 57external to the living body, provided to the external device 3, whichmeasures acceleration external to the living body; and to be made so asto detect the position of the capsule type medical device 2 based uponthe acceleration information internal to the living body which isreceived via the wireless transmission and reception section 31 of theexternal device 3, and the acceleration information external to theliving body which is measured by the acceleration sensor 57 external tothe living body.

In this case, for example, the acceleration sensor 57 external to theliving body may perform position detection of the capsule type medicaldevice 2 by, along with calculating the difference between these twoitems of acceleration information, also calculating the distance fromthis acceleration difference. By doing this, it is possible to performposition detection for the capsule type medical device 2 accurately bytaking advantage of acceleration information. It should be understoodthat it would also be possible for the above described positiondetection device 55 as well, just like the above described positiondetection device 50, to perform position detection by using some otherphysical quantity, like electromagnetic waves, radio waves, light,ultrasonic waves or the like.

Furthermore, although the external device 3 is made to detect theposition of the capsule type medical device 2, it would also be possiblefor the capsule type medical device 2 itself to constitute the positiondetection device, so as to detect its own position. As for example shownin FIG. 10, it would be acceptable for the position detection device 60to include a plurality of magnets 61 which are disposed in the vicinityof specified sites outside the living body, and a magnetic sensor notshown in the figures, which is provided to the capsule type medicaldevice 2, and which detects the magnetic field of the magnets 61; and tobe made so as to detect the position of the capsule type medical device2, based upon the magnetic field which has been detected by the magneticsensor. It should be understood that, in FIG. 10, as the variousspecified sites, the magnets 61 are arranged in the vicinities of thepylorus portion of the stomach, of the caecum, and of the anus. By doingthis, when the capsule type medical device 2 has arrived at thevicinities of the pylorus portion of the stomach, of the caecum, and ofthe anus, it is possible for the magnetic sensor to detect the magneticfield of the magnets 61 and thereby to detect its own position.

Yet further, it would also be acceptable, as shown in FIG. 11, alongwith setting up the position detection device so that, by takingadvantage of the various position detection device described above, itrecognizes the pattern of the shifting path of the capsule type medicaldevice, also to set it up so that the control section 33 of the externaldevice 3 specifies each of the sites, for example, the stomach, thesmall intestine, the colon, or the anus. By doing this, it is possibleto detect the position of the capsule type medical device 2 from thepattern of the shifting path of the capsule type medical device 2. Inparticular, it is possible to anticipate a simplification of thealgorithm, as compared with the case of detecting the position of thecapsule type medical device 2 based upon images.

Even further, although, with the above described first embodiment, theposition detection circuit is made so as to detect the orientation ofthe capsule type medical device, along with detecting its direction ofshifting by the peristaltic movement within the small intestine from thechanges of images, this is not to be considered as being limitative; forexample, as shown in FIG. 12, it would also be acceptable to arrange todetect the orientation of the capsule type medical device 2 by takingadvantage of the electrical stimulation. When, for example, the capsuletype medical device 2 has arrived at the small intestine, an electricalstimulus is applied for a brief period to the living body tissue by theelectrodes 5 at the one end or at the other end of the capsule, so thatthe capsule is caused to shift. By detecting the direction of shiftingof the capsule type medical device 2 at this time, the detection of thecapsule type medical device 2 is performed over a slower time period.After this, electrical stimulation may be applied to living body tissuefrom the electrodes 5 at the one end of the capsule or from its otherend, according to its orientation.

Still further, although it is arranged to detect the orientation of thecapsule type medical device within the living body by the abovedescribed methods, it would also be acceptable to arrange to regulatethe orientation of the capsule type medical device when it is passing aspecific site. For example, as shown in FIG. 13, along with providing apermanent magnet 65 in the interior of the capsule type medical device2, a permanent magnet 66 might be provided in the vicinity of a specificsite for example, in the vicinity of the small intestine. By doing this,when the capsule type medical device 2 passes the stomach and shiftswithin the small intestine, the capsule type medical device 2 shiftswithin the small intestine in a state in which its orientation isregulated to a fixed direction, due to its permanent magnet 65 and thepermanent magnet 66 which is arranged in the vicinity of the smallintestine. Furthermore, it would also be acceptable to utilize a coil,instead of the permanent magnet 65 which is provided to the capsule typemedical device 2, or instead of the permanent magnet 66 which isprovided to the specific site. By doing this, it is possible not togenerate magnetic force at times other than when such force is required,and, for example, it is possible to keep down to the minimum possiblelimit the interference with and the influence upon the positiondetection device which takes advantage of magnetism as described above.Accordingly, it is possible reliably to cause progress in a constantdirection, and it is easy to perform control of the electricalstimulation device.

It would also be acceptable to always use in parallel the orientationcontrol function (the magnetic induction device) with magnetismdescribed above, and to employ it in orientation control duringobservation. By doing this, the observational efficiency is enhanced.Moreover, not only is there the method with a magnet as described above,but it would also be acceptable, as for example shown in FIG. 14, toarrange to ingest the capsule type medical device 2 into the interior ofthe patient in a state in which a string 67 has been affixed to it whichcan be cut away from it, and to cut away the string 67, after it hasbeen checked that the capsule has arrived at a specific site within thesmall intestine or the like. Since, by doing this, it is possible tocause the capsule type medical device 2 to progress in a fixed directionwhile reliably regulating its orientation, accordingly it is easy toperform control of the electrical stimulation device.

Although, in the above described first embodiment, it is arranged totransmit and to receive the in-vivo information with the wirelesstransmission and reception section 12 which is provided to the capsuletype medical device 2, and with the wireless transmission and receptionsection 31 which is provided to the external device 3, it would also beacceptable, instead of the above, to emanate the in-vivo informationfrom a transmission section which is provided to at least one of thecapsule type medical device 2 and the external device 3, and to detectthis in-vivo information with a detection section which is provided tothe other one thereof.

In the above described first embodiment, it would also be acceptable forthe device which applies an electrical stimulus, such as the electrodes5 or the like which are provided to the capsule type medical device 2,to have a structure like the following.

A first variant example of the first embodiment of the capsule typemedical device system of the present invention will now be described indetail with reference to the figures. As shown in FIG. 15, this capsuletype medical device system 101 includes an external device 102 which isdisposed outside the living body, and a capsule type medical device 103which can be ingested to within the living body (to within his livingbody).

The device 102 external to the living body includes, within a main bodycase 104, a wireless transmission and reception section (an externalcommunication device) 105 which transmits and receives information toand from the capsule type medical device 103, an input device 106, adisplay device 107, an external control section 108 which controls thesevarious structural elements (device), a battery 109 which supplieselectrical power to these various structural elements, and anotheractuation switch 110.

The wireless transmission and reception section 105 includes a wirelesscircuit 111 and an antenna 112, and is equipped with the functions ofreceiving images, which are in-vivo information, which have beentransmitted and have arrived from the capsule type medical device 103,and of sending them to the external control section 108. The inputdevice 106 is a keyboard, a mouse, a joystick, a touch panel, a switch,or the like which receives data input and actuation. The display device107 displays information about the current capsule type medical device103, and displays the in-vivo information which has been received fromthat capsule type medical device 103. Furthermore, it also displays aGUI (Graphical User Interface) which supports input actuation.

The external control section 108 is structured to include a CPU (acentral processing unit) 113, a memory 114 (a storage device) whichstores in-vivo information and data, a memory 115 for program storagewhich stores a program which performs control of the external device,and a communication interface (a bus).

The capsule type medical device 103 which is ingested into the testsubject includes a capsule 121, which is a casing tightly enclosing theinterior, and which is made from a plastic or the like; and, in theinterior of this capsule, it includes a wireless transmission andreception section 122 (an internal communication device) which transmitsand receives information to and from the device 102 external to theliving body, an acquisition device 123 which acquires in-vivoinformation, a current generation device 124 which generates an electriccurrent which has a specific waveform, a plus electrode portion 125 anda minus electrode portion 126 which contact against living body tissue,a sense of force sensor (a contact detection device) 127 which measuresthe contact pressure with which this plus electrode portion 125 and thisminus electrode portion 126 contact against living body tissue, a memory128 (a storage device) which stores for a brief period the image datawhich has been acquired by the acquisition device 123, a control circuit(control section) 129 which controls these various structural elements,a battery 130 which supplies electrical power to these variousstructural elements, and a switch 131 which turns the power supply ON orOFF.

It should be understood that the current generation device 124 and theplus electrode portion 125 and the minus electrode portion 126constitute an electrical stimulation device which applies electricalstimuli to living body tissue.

The wireless transmission and reception section 122 includes an antenna132 and a wireless circuit 133, and it transmits in-vivo information tothe device 102 external to the living body, and receives signals whichthe device 102 external to the living body outputs.

The acquisition device 123 includes a CCD (Charge Coupled Device) 124and a LED (Light Emitting Diode) 135 which are provided within atransparent cover (not shown in the drawings) which is provided at oneend of the capsule 121. The CCD 134 is used for taking images variousportions inside the living body, and thus acquiring images. The LED 135illuminates the visual range of the CCD 134. It should be understoodthat, instead of the CCD 134, it would also be possible to provide asensor which monitored the living body, such as a pH sensor or the like.Furthermore, instead of the acquisition device 123, it would also bepossible to include a body sampling section which performed sampling ofliving body tissue, or a body treatment section which performedtreatment of living body tissue. Yet further, it would also be possibleto mount at least two of the acquisition device 123, the body samplingsection, and the body treatment section, at the same time.

The current generation device 124 consists of an oscillator (a waveformgenerator) 136, a gain adjustment circuit 137, a driver 138, a resistor139, and an electric current sensor 140.

The oscillator 136 generates an alternating current signal of afrequency of from a few Hz to a few tens of Hz. Furthermore, accordingto information from the control circuit 129, it is able to generate anydesired waveform pattern, such as DC output, square wave, sine wave,sawtooth wave, and the like. Yet further, in the case of a square wave,it is able to vary the ratio (the duty ratio) of the time periods whenthe amplitude is High state and when it is in Low state. For a sawtoothwave, it is able to adjust the ratio of the time period while thevoltage is rising to the time period when it is dropping. It should beunderstood that the selection of the waveform pattern for the oscillator136, and of whether it is outputting or not outputting, is controlled bythe control circuit 129.

The gain adjustment circuit 137 amplifies the output of the oscillator136. The amplification ratio is controlled by the control circuit 129.Furthermore, the gain adjustment circuit 137 also functions as alimitation circuit which monitors the output of the electric currentsensor 140, and, if this electric current which flows is greater than aset value, lowers the gain and limits the electric current value.

The driver 138 is connected to the output of the gain adjustment circuit137, and is a circuit which performs voltage electric current transferin order to control the electrical stimulus which is applied to livingbody tissue with an electric current value.

The resistor 139 controls the electric current which flows to the livingbody, and is for preventing excess electric current; one of its ends isconnected to the output of the driver 138, while its other end isconnected to the plus electrode portion via the electric current sensor140.

The electric current sensor 140 measures the electric current valuewhich is supplied from the resistor 139 to the plus electrode portion125, in other words the electric current value which is applied to theliving body. The output of this electric current sensor 140 is connectedto the control circuit 129 and the gain adjustment circuit 137.

As shown in FIG. 16, the plus electrode portion 125 includes a switchingelement 141 (a first switching device) which is connected to theelectric current sensor 140, and plus electrodes 142 which is connectedto this switching element 141. These plus electrodes 142 are one set ofelectrodes which are connected to the high electrical potential side,and, in this first variant example, there are six of these pluselectrodes 142 a through 142 f. As will be described hereinafter, aportion of each of these plus electrodes 142 a through 142 f is exposedto the exterior of the capsule 121. The switching element 141 has sixcontact points, and each one of these is connected to one of the pluselectrodes 142 a through 142 f. These contact points of this type ofswitching element 141 are changed over, based upon command signals fromthe control circuit 129.

The minus electrode portion 126 includes a switching element 143 (asecond switching device) which is connected so as to be at the sameelectrical potential as the ground of the other circuits within thecapsule type medical device 103 (a standard electrical potential), andminus electrodes 144 which are connected to this switching element 143.These minus electrodes 144 are another set of electrodes which areconnected to the low electrical potential side, and, in this firstvariant example, there are six of these minus electrodes 144 a through144 f, corresponding to the number of the plus electrodes 142. A portionof each of these minus electrodes 144 a through 144 f, as will bedescribed hereinafter, is exposed to the exterior of the capsule 121.The switching element 143 has six contact points, and each one of theseis connected to one of the minus electrodes 144 a through 144 f. Thesecontact points of this type of switching element 143 are changed over,based upon command signals from the control circuit 129.

As shown in FIG. 17, the sense of force sensor 127 includes: deformationgauges 145 a through 145 f, 146 a through 146 f, 147 a through 147 f,and 148 a through 148 f which are each respectively fitted to the pluselectrodes 142 a through 142 f (refer to FIG. 16) and the minuselectrodes 144 a through 144 f (refer to FIG. 16); an amp 150 fordeformation gauging which detects the voltages of bridge circuits 149 athrough 149 f which are constituted by the deformation gauges 145 athrough 148 f; and a switching circuit 151 for deformation gauging whichchanges over the one of the bridge circuits 149 a through 149 f whosevoltage is detected by the amp 150 for deformation gauging.

The amp 50 for deformation gauging is a device which monitors thecontact pressure of the electrodes 142 a through 142 f and 144 a through144 f against living body tissue, and it includes a voltage source 152which applies a predetermined voltage to the bridge circuits 149 athrough 149 f, a voltage meter 153 which measures the voltage of thebridge circuits 149 a through 149 f, and a voltage load transducer 154which is connected to the voltage meter 153. This voltage loadtransducer 154 converts the voltage which has been detected by thevoltage meter 153 into an amount of force (a pressure). The output ofthis voltage load transducer 154 is connected to the control circuit129.

The switching circuit 151 for deformation gauging includes a switchingcircuit 151 a which is connected to the high electrical potential sideof the voltage source 152 of the amp 150 for deformation gauging, aswitching circuit 151 b which is connected to the low electricalpotential side of the voltage source 152, a switching circuit 151 c anda switching circuit 151 d which are connected to the input of thevoltage meter 153. Each of the switching circuits 151 a through 151 dhas six contact points corresponding to the numbers of the electrodes142 a through 142 f and 144 a through 144 f. In the switching circuit151 a and the switching circuit 151 b, the contact points are connectedby the control circuit 129 so that voltage is applied to one of thebridge circuits 149 a through 149 f. Furthermore, in the switchingcircuit 151 c and the switching circuit 151 d, the contact points areconnected by the control circuit 129 so that the voltage which isgenerated by the bridge circuit 149 a through 149 f to which voltage isapplied can be measured.

The bridge circuits 149 a through 149 f include four deformation gauges.For example, the bridge circuit 149 a includes the four deformationgauges 145 a, 146 a, 147 a, and 148 a. The one end of the deformationgauge 145 a and the one end of the deformation gauge 147 a are connectedto the same contact point of the switching circuit 151 a, and the oneend of the deformation gauge 146 a and the one end of the deformationgauge 148 a are connected to the same contact point of the switchingcircuit 151 b. Furthermore, the other end of the deformation gauge 147 aand the other end of the deformation gauge 148 a are connected to thesame contact point of the switching circuit 151 c, and the other end ofthe deformation gauge 145 a and the other end of the deformation gauge146 a are connected to the same contact point of the switching circuit151 d. It should be understood that, as will be described hereinafter,the deformation gauge 145 a and the deformation gauge 146 a are fittedto the plus electrode 142 a. The deformation gauge 147 a and thedeformation gauge 148 a are fitted to the minus electrode 144 a which isdisposed adjacent to that plus electrode 142 a. Moreover, following thispattern, each of the bridge circuits 149 b through 149 has the samestructure as the bridge circuit 149 a.

The shape of the capsule 121 of this capsule type medical deice 103, andan example of the arrangement of the plus electrodes 142 and the minuselectrodes 144, will now be explained using FIG. 18, FIG. 19, and FIG.20. It should be understood that FIG. 18 is an external view of thecapsule type medical device. FIG. 19 is a figure showing the externalappearance of its rear portion, while FIG. 20 is a sectional view in thevicinity of the rear portion.

As shown in FIG. 18, the capsule 121 is shaped as a circular cylinder,and one tip portion 155 thereof, which is its one end which ispositioned at the left side in the figure, has a curved surface which isclose to a hemisphere. A transparent portion is provided upon this tipportion 155, and the acquisition device 123 and so on are disposed atthe interior thereof. Furthermore, the outer diameter of the rearportion 156, which is the other end which is positioned at the rightside in the figure, is reduced linearly more than is the tip portion155, and its final rear end is closed by a rounded shape. It should beunderstood that although, in the following, the explanation is made interms of the tip portion 155 being the front end of this capsule typemedical device 103 with respect to its direction of progress, it mayalso happen that the front and the rear of the capsule type medicaldevice 103 are reversed within the coelom.

As shown in FIG. 19, six openings 157 are formed radiating outwards uponthis rear portion 156 at equal intervals. These openings 157 haveroughly rectangular forms, facing from the central axis towards the sidesurface of the capsule 121 (its peripheral edge in FIG. 19), and, ineach of them, the plus electrodes 142 a through 142 f and the minuselectrodes 144 a through 144 f are respectively arranged so as to be inparallel, and moreover so that the one portions of each of their endsare projected to the outside. In concrete terms, in each of the openings157, the electrode 142 a and the electrode 144 a, the electrode 142 band the electrode 144 b, the electrode 142 c and the electrode 144 c,the electrode 142 d and the electrode 144 d, the electrode 142 e and theelectrode 144 e, and the electrode 142 f and the electrode 144 f, arerespectively arranged so as to be in parallel. It should be understoodthat the gaps which are formed in the openings 157 in the state in whichthe electrodes 142 and 144 are inserted into them are filled up with asoft adhesive material 158, so that they become watertightconstructions. By using this soft adhesive material 158, it becomespossible to measure the contact pressure between the electrodes 142 and144 and the living body tissue with the deformation gauges 145 a through148 f.

As shown in FIG. 20, in the interior of the capsule 121, there is fixedan electrical circuit substrate 159. Upon this electrical circuitsubstrate 159, there are fitted the plus electrodes 142 (only the pluselectrode 142 a is shown in FIG. 20) and the minus electrodes 144 (onlythe minus 144 d is shown in FIG. 20), the switching elements 141 and143, and the amp for deformation gauging 150 and the switching circuit151 for deformation gauging of the sense of force sensor 127.

Furthermore, a flexible substrate 160 is fitted at one end of theelectrical substrate 159. This flexible substrate 160 is used forexchanging signals from the various circuits upon the electricalsubstrate 159 with the control circuit 129. Furthermore, it also servesthe purposes of supplying source power to the various circuits upon theelectrical circuit substrate 159, and of electrically connectingtogether the electric current sensor 140 and the plus electrode portions125.

The plus electrodes 142 include contact portions 161, the one ends ofwhich project from the capsule 121, and base portions 162 which extendfrom these contact portions 161; and these base portions 162 are mountedto the electrical circuit substrate 159.

Portions of elongated portions of these contact portions 161 are formedin the shape of curved surfaces whose shape is approximately the same asthat of the slope of the capsule 121, and portions of these curvedsurfaces are exposed at the exterior of the capsule 121. In concreteterms, they include a bottom surface which follows along the centralaxis C, and a plane surface which extends outwards in the radialdirection of the capsule 121 from the tip portion 155 side of the bottomsurface (refer to FIG. 18); and a curved surface is formed from theposition of the tip end of the plane surface (its outer end in theradial direction), towards the position of the tip end of the bottomsurface (its rear end along the central axis C).

The base portion 162 has a shape which extends along the central axis Cfrom the plane surface of the contact portion 161, and which is longerand thinner than the contact portion 161. Furthermore, V grooves 164 and165 are formed between the contact portions 161 and the portions whichare fitted to the electrical circuit substrate 159. The V groove 164 isprovided upon the surface 166 which extends along the lengthwisedirection of the capsule 121 and faces the central axis C, so as to beorthogonal to the lengthwise direction along the central axis C.Moreover, the V groove 165 is provided upon the surface 167 which is onthe other side from the surface 166, and is provided more towards thecontact portions 161 than the V grooves 164, again so as to beorthogonal to the lengthwise direction along the central axis C. The Vgroove 164 makes the base portion 162 easily bent towards the centralaxis C direction, while the V groove 165 makes the base portion 162easily bent towards the direction which is opposite to the central axisC direction. Therefore, if a force in the direction of the central axisC acts upon the contact portion 161 of the electrode 142, or if a forceof the opposite orientation acts thereupon, the base portion 162 bendsin the vicinities of the V grooves 164 and 165, and is deformed so as toyield to this type of force. With this type of plus electrode 142, thedeformation gauge 145 a of the sense of force sensor 127 is fitted at asite on the surface 166 more towards the contact portion 161 than the Vgroove 164. Furthermore, the deformation gauge 146 a of the sense offorce sensor 127 is fitted at a site on the surface 167 more towards theelectrical circuit substrate 159 than the V groove 165.

Furthermore, the minus electrodes 144 as well have the same structure.That is, a V groove 164 is provided upon the surface 166 side of thebase portion 162, and a V groove 165 is formed on its surface 167 side;and, if a force in the direction of the central axis C, or a force inthe other direction, acts upon the contact portion 161, the base portion162 in the neighborhood of the V grooves 164 and 165 bends. Thedeformation gauge 148 d of the sense of force sensor 127 is fitted at asite on the surface 166 more towards the contact portion 161 than the Vgroove 164. Furthermore, the deformation gauge 147 d of the sense offorce sensor 127 is fitted at a site on the surface 167 more towards theelectrical circuit substrate 159 than the V groove 165.

It should be understood that the reason for the four deformation gaugeswhich constitute each one of the bridge circuits 149 a through 149 fbeing fitted so as to be distributed between one adjacent set of a pluselectrode 142 and a minus electrode 144, is because the set of a pluselectrode 142 and a minus electrode 144 which are adjacent in thismanner exhibit behavior almost like one body, and are in the samecontact state in relation to living body tissue.

Observation within the body of the test subject with a capsule typemedical device system 101 which has this type of structure will now beexplained in the following.

First, the test subject is insulated, and the device 102 external to theliving body is fitted to his body portion with a belt or the like. Next,the capsule type medical device 103 is ingested into the test subjectvia mouth. This capsule type medical device 103, upon command from thedevice 102 external to the living body, or upon command from a timercircuit or an operational program which is provided to the controlcircuit 129, along with emitting light from the LED 135, also operatesthe CCD 134, and takes images of the inside of the living body. Theimage data which has been acquired by this image is digitalized, and isstored for a brief period in the memory 128 in a compressed state,according to requirements. This image data which has been stored in thememory 128 is transmitted via the wireless transmission and receptionsection 122 to the device 102 external to the living body.

In the device 102 external to the living body, the image data which hasbeen received by the wireless transmission and reception section 105 isdata processed by the CPU 113 within the control section 108 external tothe living body, and is stored in the memory 114. The images of theinside of the living body which have been taken images by the capsuletype medical device 103 are thus accumulated in the memory 114 of thedevice 102 external to the living body. Furthermore, according torequirements, these images are outputted upon a display device 107.

The external control section 108 compares together two images which havebeen taken images by the capsule type medical device 103 at differenttime instants, and infers the shift amount of the capsule type medicaldevice 103 within the coelom. As a method for inferring the shiftamount, for example, a correlation method of image processing may beutilized. In the external control section 108, a threshold value for thecorrelation coefficient is set in advance, and, if the correlationcoefficient of two images which follow one another in time is greaterthan the threshold value, then it is decided that the shift amount ofthe capsule type medical device 103 is insufficient. On the other hand,if the correlation coefficient is less than the threshold value, then itis decided that the capsule type medical device 103 is shifting withinthe coelom.

If it is decided that the shift amount of the capsule type medicaldevice 103 is small, and moreover when shifting of the capsule typemedical device 103 is required, then the capsule type medical device 103is propelled. In concrete terms, the device 102 external to the livingbody transmits a command from the wireless transmission and receptionsection 105 to urge electrical stimulation, and, upon receipt of thiscommand, the capsule type medical device 103 flows electric current fromthe plus electrodes 142 a through 142 f via the living body tissue tothe minus electrodes 144 a through 144 f, thus applying an electricalstimulus to the living body tissue, so as to cause the luminar tissue toshrink.

When the capsule type medical device 103 flows the electric current inthis manner, initially, it operates the sense of force sensor 127, andselects the plus electrodes 142 a through 142 f and the minus electrodes144 a through 144 f through which the electric current is to flow. Inother words, as shown in FIG. 18, the sense of force sensor 127 changesover the contact points of the switching circuits 151 a, 15 b, 151 c,and 151 d which are included in the switching circuit 151 fordeformation gauging in order while maintaining synchrony between them,and acquires change of the resistance value of the bridge circuits 149 athrough 149 f which consist of the deformation gauges 145 a through 145f, 146 a through 146 f, 147 a through 147 f, and 148 a through 148 f asvoltage, which it converts into contact pressure with the voltage loadtransducer 154.

The contract pressure which has been detected in this manner is inputtedto the control circuit 129. In the control circuit 129, it is determinedwhether or not the contact pressure which has been detected by the senseof force sensor 127 exceeds a predetermined value which is set inadvance.

If the contact pressure is smaller than the predetermined value, thenthe control circuit 129 decides whether one or more of each of theelectrodes 142 and 144 on the plus side and on the minus side is noteffectively in contact with living body tissue, and it continues themonitoring of the contact pressure until one of more of each of theelectrodes 142 and 144 comes to be in a contacting state. It should beunderstood that this monitoring of the contact pressure may be performedcontinuously, or may be performed intermittently.

On the other hand, if the contact pressure which has been detected bythe sense of force sensor 127 is greater than or equal to thepredetermined value, then it is decided that the electrodes 142 athrough 142 f and 144 a through 144 f which are fitted to its bridgecircuit 149 a through 149 f are sufficiently in contact with living bodytissue, and it is decided that it is possible to flow electric currentfrom these electrodes 142 a through 142 f and 144 a through 144 f toliving body tissue.

If it has been decided that one or more of the electrodes 142 and 144 oneach of the plus side and the minus side is effectively in contact, thenthe control circuit 129 changes over the switching element 141 of theplus electrode portion 125, and connects the plus electrode 142 athrough 142 f for which the predetermined contact pressure is obtainedto the current generation device 124. Furthermore, it changes over theswitching element 143 of the minus electrode portion 126, and connectsthe minus electrode 144 a through 144 f for which the predeterminedcontact pressure is obtained to the ground of the other circuits withinthe capsule type medical device 102. It should be understood that, inFIG. 16, the situation is shown in which the switching elements 141 and143 are set so that the electric current flows from the plus electrode142 f to the minus electrode 144 c.

Next, the control circuit 129 sets the oscillation waveform of theoscillator 136 of the current generation device 124 and the gain of thegain adjustment circuit 137. Although it will be acceptable for thevalue of the gain which is set to be a value which is set in advance, itwould also be acceptable to set the gain by inferring the contactimpedance from the contact pressures between the electrodes 142 and 144which are selected and living body tissue. In this case, if the contactpressure is greater, the gain is set to be smaller, since the contactimpedance is smaller. Moreover, if the contact pressure is smaller, thegain is set to be greater, since the contact impedance is greater.Furthermore, it is possible to apply a stabilized electric current tothe living body tissue, by monitoring the value of the electric currentsensor 140 when the electric current is flowing through the living bodytissue, and by feeding it back to the setting of the gain of the gainadjustment circuit 137.

When the above described setting has been completed, the control circuit129 supplies the electric current which is generated by the currentgeneration device 124 to the plus electrode portion 125. In concreteterms, it operates the oscillator 136 and generates a signal of thepredetermined waveform, amplifies this signal with the gain adjustmentcircuit 137, and converts it into electric current with the driver 138.It supplies this electric current via the electric current sensor to theplus electrode portion 125, and flows this electric current via theliving body tissue between the plus electrode 142 and the minuselectrode 144.

Thus, an electric current signal according to the voltage waveform ofthe oscillator 136 is applied to the living body tissue, the luminaltissue shrinks. Since this shrinkage operation acts so as to push outthe inclined surface of the rear portion 156 (refer to FIG. 18) of thecapsule 121 upon which the electrodes 142 and 144 are arranged, therebythe capsule type medical device 103 is caused to be propelled with itstip portion 155 on the forward side. When the capsule type medicaldevice 103 is thus caused continually to advance, it will be acceptableto continue to flow the electric current to the same plus electrode 142and minus electrode 144, or to detect the contact pressure with thesense of force sensor 127, to select in order the most suitablecombination of the electrodes 142 and 144, and to flow the electriccurrent to them.

The control of the electric current for the current generation device124 will now be explained using FIG. 15 and FIG. 21. FIG. 21 shows thechange of the voltage waveform which is outputted from the gainadjustment circuit.

Initially, the oscillator 136 generates a trapezoidal wave, and thistrapezoidal wave is amplified by the gain adjustment circuit 137 by again which is set in advance; for example, as shown in FIG. 21, avoltage waveform f1 may be outputted of which the maximum voltage is V1.This voltage waveform f1 is converted by the driver 138 into an electriccurrent value, and this electric current which has been obtained byconversion is flowed, via the resistor 139 and the electric currentsensor 140, to the living body tissue from the plus electrode portion125, and recirculates from the electric current section 126.

At this time, the control circuit 129 monitors the value of the electriccurrent sensor 140, so as not to apply an electric current of greaterthan or equal to a predetermined electric current value IL to the livingbody tissue. If the electric current value is less than or equal to IL,then it continues to flow an the electric current according to thevoltage waveform f1. On the other hand, if the electric current value isgreater than IL, then either it stops the oscillator 136, or it lowersthe gain of the gain adjustment circuit 137, or performs both theseactions, so that, during this period, the application of the electricalstimulus is stopped therefore, the waveform of the output voltage inthis type of case comes to be like the voltage waveform f2 shown by thesolid lines.

Next, the control circuit 129 sets the gain so that the voltage waveformwhich is outputted from the gain adjustment circuit 137 becomes thevoltage V2 which is lower than the voltage V1, like the voltage waveformf3. The value of the voltage V2 may be set in advance, or may beinferred by the control circuit 129 from the time period from when theelectric current corresponding to the voltage V1 is applied to theliving body, until the electric current value IL is exceeded. If, eventhough the gain is reduced in this manner, the electric current value ILis exceeded, then, after the output waveform becomes like the voltagewaveform f2 again, the above described procedure is repeated.

In other words, the control circuit 129 sets the gain so that thevoltage waveform which is outputted from the gain adjustment circuit 137becomes a voltage V3 which is less than the voltage V2. If, with thisgain, the electric current becomes less than the electric current valueIL, then it continues to supply the electric current with this gain.Since, by controlling the gain by doing this, it is possible to limitthe electric current and to apply an appropriate electrical stimulus tothe living body, accordingly it is possible to obtain a propulsive forcefor the capsule type medical device in a stable manner.

It should be understood that since, with this type of control, it neverhappens that an electric current of greater than the electric currentvalue IL which is set in advance comes to be applied to the living body,accordingly it would be possible to omit the resistor 139.

Furthermore, in order to perform the control of the electric currentwith good responsiveness, it would also be possible to employ astructure in which a limit value for the value of the electric currentsensor 140 is decided by a comparator or the like (not shown in thedrawings), and which stop to output it directly.

Since, according to this first variant example, it has been arranged toinclude the plurality of electrodes 142 a through 142 f and 144 athrough 144 f, and to flow the electric current after checking thecontact state between the living body tissue and the electrodes 142 athrough 142 f and 144 a through 144 f with the sense of force sensor127, accordingly it becomes possible to flow the electrical current in astabilized manner. Moreover, it becomes possible to flow the electriccurrent to living body tissue reliably. Accordingly, it becomes possibleto stabilize the propulsion of the capsule type medical device. Since itis arranged to provide the electrodes 142 a through 142 f and 144 athrough 144 f in plurality, and to switch between the plurality ofelectrodes 142 a through 142 f and 144 a through 144 f in order, so asto select the electrode through which to flow the electric current,accordingly, it becomes easy to apply an electrical stimulus to the bodyand to stabilize the capsule type medical device, and moreover it ispossible to propel it reliably.

Furthermore, by adjusting the gain by feeding back the electric currentvalue, it is possible to limit the electric current value to less thanor equal to a predetermined value. Accordingly, it is possible to applythe electrical stimulus to the living body tissue in a stabilizedmanner. Moreover, it is possible to lengthen the life of the battery130.

Thus, since it is possible to apply the electrical stimulus to theliving body tissue in correspondence with the site within the livingbody which is obtained with the first embodiment, along with thebeneficial effect that it is possible to perform observation with goodefficiency, it is also possible to obtain the beneficial effects asdescribed above.

It should be understood that it would also be acceptable to gentlydeform the edge portions of the voltage waveform which is outputted fromthe gain adjustment circuit 137, like the voltage waveform f4 shown inFIG. 22, so that its corners are made like a round square wave. Since,by making its edge portions from a square wave, the high frequencycomponent is no longer generated when this type of voltage waveform isutilized, therefore the application of unintentional high frequencyelectric currents is eliminated. Accordingly, it is possible to applythe electrical stimulus in a stabilized manner.

Furthermore, it would also be acceptable to form the voltage waveformwhich is outputted from the gain adjustment circuit 137 as a triangularwaveform such as one which rises and falls in a step form, like thevoltage waveform shown in FIG. 23. Since, by utilizing this type ofwaveform, even though a high frequency component is generated, it ispossible to make its power low, therefore it is possible to preventelectric currents of an unintentionally high frequency from beingapplied to the living body tissue at a strength greater than intended.Accordingly, it is possible to apply the electrical stimulus in astabilized manner.

Next, a second variant example of the first embodiment of the capsuletype medical device system of the present invention will be explained indetail with reference to the drawings. It should be understood that, tostructural elements which are the same as in the first variant example,the same reference symbols are affixed, and overlapped explanation isomitted.

In the capsule type medical device according to this second variantexample, its elongated capsule has a long and thin shape along itsdirection of advance and retreat, and it is characterized in that aplurality of electrodes are arranged along its longitudinal direction ina number of stages.

As shown in FIG. 24, on the side surface of the capsule 181 of thiscapsule type medical device 180, from its tip portion 185 to its rearportion 186, along the longitudinal direction (its central axis C inFIG. 24), there are formed three projecting portions 187, 188, and 189in a symmetrical saw-tooth wave shape with respect to the central axisC. From their most projected portions, these projecting portions 187,188, and 189 have inclined portions 187 a, 188 a, and 189 a which slopetowards the tip portion 185, and inclined portions 187 b, 188 b, and 189b which slope towards the rear portion 186. The slope of the inclinedportions 187 b, 188 b, and 189 b is gentler than that of the inclinedportions 187 a, 188 a, and 189 a, so that, relatively, they can contactagainst living body tissue more easily. Furthermore, upon each of theseinclined portions 187 b, 188 b, and 189 b, there is provided a pluselectrode 142 and a minus electrode 144. At least one group of a pluselectrode 142 and a minus electrode 144 are provided upon each singleprojecting portion 187, 188, and 189.

This capsule type medical device 180 uses a sense of force sensor asshown in FIG. 18, which detects the contact pressure against living bodytissue of the plus electrodes and the minus electrodes which areprovided to each of the projecting portions 187, 188, and 189. A pluselectrode 142 and a minus electrode 144 which have a predeterminedcontact pressure are selected by the control circuit 129, and electricalstimulation is applied to the living body tissue thereby. The electricalcurrent at this time is controlled by using the gain adjustment circuitand so on.

According to this second variant example, it is possible to obtain thesame beneficial effects as with the first variant example of the firstembodiment. Furthermore, it is possible to increase the number oflocations at which electrical stimulation can be applied to living bodytissue, since, upon the outer periphery of a cross section orthogonal tothe longitudinal direction of the capsule 181, the first stageelectrodes 142 and 144 are positioned upon the projecting portion 187towards the tip portion 185, the second stage electrodes 142 and 144 arepositioned upon the projecting portion 188 more to the rear portion 186than the projecting portion 188, and the third stage electrodes 142 and144 are positioned upon the projecting portion 189 towards the rearmostportion 186. Accordingly, it is possible to propel this capsule typemedical device 180 with good efficiency.

It should be understood that although, in FIG. 24, a structure is shownin which the electrodes 142 and 144 are arranged in multiple stages onboth side surfaces of the capsule 181 of the capsule type medical device180, if the projecting portions 187, 188, and 189 are provided so as tosurround the outer periphery of the cross section orthogonal to thelongitudinal direction of the capsule 181, it would also be possible toarrange a greater number of the plus electrodes 142 and the minuselectrodes 144.

Yet further, it would also be acceptable to arrange to select one groupeach of the electrodes 142 and 144 from each of the projecting portions187, 188, and 189, and, at a maximum, to flow electric current vialiving body tissue between these three groups of plus electrodes 142 andminus electrodes 144.

Next, a third variant example of the first embodiment of the capsuletype medical device system of the present invention will be explained indetail with reference to the drawings. It should be understood that, tostructural elements which are the same as in the first and secondvariant examples, the same reference symbols are affixed, and overlappedexplanation is omitted.

This third variant example is characterized in that the electrodes arearranged so as to be able to propel the capsule type medical device bothforwards and backwards.

As shown in FIG. 25, the capsule 191 of this capsule type medical device190 has a large diameter portion 197 between from its tip portion 195 toits rear portion 196, such that its outer diameter increases in thedirection which is roughly orthogonal to the central axis C along thelongitudinal direction of the long and thin capsule 191. This largediameter portion 197 has an inclined portion 197 a which slopes towardsthe tip portion 195, and an inclined portion 197 b which slopes towardthe rear portion 196; and, upon each of these inclined portions 197 aand 197 b, there is provided at least one group of a plus electrode 142and a minus electrode 144. Furthermore, upon the rear portion 196 of thecapsule 191 as well, there is provided at least one group of a pluselectrode 142 and a minus electrode 144.

The ends of the electrodes 142 and 144 project towards the living bodytissue from the capsule 191. The electrodes 142 and 144 which aredisposed upon the inclined portion 197 a project towards the directionof progress (i.e. towards the tip portion 195). And the electrodes 142and 144 which are disposed upon the inclined portion 197 b projecttowards the direction which is opposite to the direction of progress(i.e. towards the rear portion 196). The plus electrodes which arearranged in this manner, constitute the plus electrode portion 125, asshown in FIG. 16, and are connected to the current generation device 124(refer to FIG. 15).

The switching element 141 may be made so as to change over theelectrical conduction state of all of the plus electrodes 142.Furthermore, the switching element which changes over the pluselectrodes which are disposed upon the inclined portion 197 a, and theswitching element which changes over the plus electrodes 142 which aredisposed upon the inclined portion 197 b and upon the rear portion 196,are constituted separately, and, for each of these switching elements,it will be acceptable to change over the plus electrodes 142independently. The same holds for the minus electrodes 144.

Next, the operation of this capsule type medical device 190 will beexplained.

If the tip portion 195 is oriented in the direction of progression, whenthe capsule type medical device 190 is to be caused to advance, thecontact pressure against living body tissue is detected from theelectrodes 142 and 144 of the inclined portion 197 b and the electrodes142 and 144 of the rear portion 196. Electric current is supplied to theplus electrodes 142 and the minus electrodes 144 which have beenselected by the control circuit 129 based upon the contact pressure, sothat an electrical stimulus is applied to the living body tissue. On theother hand, when the capsule type medical device 190 is to be caused toretreat, then electric current is flowed via the living body tissue tothe plus electrodes 142 and the minus electrodes 144 which are selectedfrom among the electrodes 142 and 144 upon the inclined portion 197 a,based upon the contact pressure.

Furthermore, if the tip portion 195 is oriented in the oppositedirection to the direction of progress, while the rear portion 196 isoriented in the direction of progress, then, when advancing, electrodesare utilized which have been selected from the electrodes 142 and 144upon the inclined portion 197 b and from the electrodes 142 and 144 uponthe rear portion 196; while, when retreating, electrodes are utilizedwhich have been selected from the electrodes 142 and 144 upon theinclined portion 197 a.

According to this third variant example, it is possible to obtain thesame beneficial effects as with the first and second variant examples.Furthermore, by selecting the electrodes to which to supply electricalpower, it is possible to change over the direction of progress of thecapsule type medical device 190 by electrical stimulation.

It should be understood that the present invention is not limited tothese various embodiments; it can be applied widely. For example,instead of selecting the electrodes 142 and 144 with the sense of forcesensor 127, it would also be acceptable to select the electrodes 142 and144 by using a voltage meter which is provided between the input sidesof the plus electrode portions 125 and the output sides of the minuselectrode portions 126. In concrete terms, it will be acceptable, whileswitching over the electrodes 142 and 144, to apply a very weak electriccurrent to the living body tissue from the current generation device andto measure the voltage between the plus electrode 142 which has beenselected and the minus electrode 144 which has been selected, with thecontrol circuit 129 calculating the impedance between the electrodes andselecting electrodes 142 and 144 like those for which the impedance isbelow a predetermined value to apply the electrical stimulus. The samebeneficial effects may be obtained when measuring the impedance, byapplying a fixed voltage, and by measuring the electric current valuewhich flows at this time between the electrodes 142 and 144.

Furthermore, although the movement of the capsule type medical device103, 180, or 190 is inferred according to change of the images taken bythe CCD 134, it would also be acceptable to provide an accelerationsensor to the capsule type medical device 103, 180, or 190 (moredesirably, a three dimensional acceleration sensor), and to determinethat the position of the capsule type medical device 103, 180, or 190has not changed if no acceleration has been detected over a long timeperiod, and to perform control so as to shift over to the procedure ofapplying an electrical stimulus. In this case there is the beneficialeffect that the control becomes convenient and simple, since themovement of the capsule type medical device 103, 180, or 190 is detectedonly by the output of the acceleration sensor, and accordingly there isno requirement for any decision as to the requirement or otherwise forapplication of electrical stimulation to be made according to theperformance of communication with the device 102 external to the livingbody. It should be understood that, instead of the acceleration sensor,it would also be acceptable to utilize a speed sensor.

Yet further, it would also be acceptable to provide an accelerationsensor to the device 102 external to the living body as well, and todecide that the movement of the capsule type medical device 103, 180, or190 with respect to the lumen has ceased when the difference hasdisappeared between the output values of the two acceleration sensorsi.e., the difference between the output value of the sensor which isprovided to the capsule type medical device 103, 180, or 190, and theoutput value of the sensor which is provided to the device 102 externalto the living body. By doing this, even if the test subject has moved,it is possible to infer movement of the capsule type medical device 103,180, or 190 with respect to the lumen by canceling out the operationthereof. It should be understood that the decision as to the presence orabsence of shifting based upon the output of the acceleration sensormight be performed by the control circuit 129 of the capsule typemedical device 103, 180, or 190, or might be performed by the controlsection 108 external to the living body of the device 102 external tothe living body.

Next, with regard to the timing by which the imaging element 20 and theoptical system 21 such as the LED or the like of the first embodiment ofthe capsule type medical device system of the present invention iscaused to operate, a preferred example thereof will be explained indetail, as a fourth variant example of the first embodiment.

The capsule type medical device 201 of this fourth variant example, asshown in FIG. 26, includes: a capsule shaped casing 202; an imagingdevice 203 which takes images of the inside of the living body; anelectrical stimulation device 205 which is provided upon the outersurface of the casing 202, and which includes electrodes 204 which applyelectrical stimulation to living body tissue; and a timing controller(i.e. a control section) 206 which causes each of the imaging device 203and the electrical stimulation device 205 to operate at its owndifferent and separate timing.

The casing 202 is made from a plastic material or the like so as tightlyto enclose its interior, and a transparent cover which is not shown inthe figures is provided at one end thereof. At the inside of thistransparent cover, there is disposed an optical system which consists ofan imaging element not shown in the drawings which obtains images by theimaging device various portions of the inside of the living body, and aLED or the like which illuminates the visual range of this imagingelement by emitting illumination light. Furthermore, the imaging elementreceives a signal from an imaging circuit 210 and is driven thereby. Inother words, the imaging element and the imaging circuit 210 constitutean imaging device 203.

The electrodes 204 are provided as a pair at the one end of the casing202, so as to sandwich the axial line of the casing 202, and, uponreceipt of a signal from an electrical stimulation circuit 211, they arecapable of flowing an electrical current to living body tissue and thusapplying an electrical stimulus. These electrodes 204 and thiselectrical stimulation circuit 211 constitute the electrical stimulationdevice 205.

Furthermore, the electrodes 204 are transparent electrodes which areoptically transparent. In other words, the electrodes 204 are made fromtransparent electrically conductive layers which have a combination ofhigh transparency and electrical conductivity. Such a transparentelectrically conductive layer, for example, may be made by forming, upona glass substrate, a thin layer of tin oxide with a little addedfluorine, or a thin layer of indium oxide with a little added ammonia.

Within the casing 202, there are provided a memory 212 which records theimages of the inside of the living body which have been taken images bythe imaging device 203, and a battery 213 which supplies electricalpower to the various structural components.

As shown in FIG. 27, the timing controller 206 sets in advance theoperating time periods so that the imaging device 203 and the electricalstimulation device 205 each operates individually and separately. Bydoing this, the operational timings are mutually displaced from oneanother. In other words, the timing controller 206 initially turns theimaging circuit 210 ON and acquires images; and thereafter it repeatsthe actions of: along with turning the imaging circuit 210 OFF, alsoturning the electrical stimulation circuit 211 ON and applying anelectrical stimulus, and thereafter, along with turning the electricalstimulation circuit 211 OFF, also turning the imaging circuit 210 ON.

The case of taking an image of the interior of the body of a person whois the subject of investigation with a capsule type medical device 201which has this type of structure will now be explained in the following.

When the capsule type medical device 201 is ingested by the person whois the subject of investigation into the interior of his body, a switchwhich is not shown in the figures comes to be turned ON, and electricalpower is supplied from the battery 213 to the various structuralcomponents. therefore, as shown in FIG. 27, the timing controller 206operates the imaging device 203 and the electrical stimulation device205 at their individual separate timings. In other words, the timingcontroller 206 first operates the imaging circuit 210 and performsimages of the inside of the living body with the imaging element. Imageswhich are taken images are recorded in the memory 212. Next, at the sametime as turning the imaging circuit 210 OFF, the timing controller 206also operates the electrical stimulation circuit 211, and flows anelectrical current so as to apply an electrical stimulus to the livingbody tissue from the electrodes 204. Therefore, the operation ofshrinking the living body tissue of, for example, the small intestine orthe like (the intestinal wall) is performed. By this shrinking of theliving body tissue, the one end of the casing 202 of the capsule typemedical device 201 is pushed out by the living body tissue, so that itshifts within the alimentary canal.

After the shifting, at the same time as turning the electricalstimulation circuit OFF, the timing controller 206 causes the imagingcircuit 210 to operate, and thereby performs images of the inside of theliving body for a second time.

According to this fourth variant example, since the timing controller206 operates the imaging device 203 and the electrical stimulationdevice 205 at their individual different timings, images are notacquired while applying electrical stimulation to the living bodytissue. In other words, since an image is performed only in the state ofreliably being stopped, or, in detail, when shifting at a slow speedsuch as due to peristaltic movement of the small intestine or the like,accordingly it is possible to acquire desirable images which have noblurring or the like. Accordingly, after this, when detecting the stateof health of the person who is the subject of investigation based uponimages which are recorded in the memory 212, it is possible to enhancethe reliability thereof.

Furthermore, since the electrodes 204 are transparent electrodes, theimaging device 203 is able to obtain proper images accurately,irrespective of the positions in which these electrodes 204 arearranged. Therefore, since there is no limitation imposed upon thepositions for arrangement of the electrodes 204, the freedom of designis enhanced.

Accordingly, since it is possible to apply an electrical stimulus to theliving body tissue in correspondence with the site within the livingbody which is obtained by the first embodiment, along with thebeneficial effect that it is possible to perform observation with goodefficiency, it is also possible to obtain the beneficial effects asdescribed above.

Next, a fifth variant example of the first embodiment of the capsuletype medical device system of the present invention will be explained indetail with reference to the drawings. It should be understood that, tostructural elements which are the same as in the fourth variant example,the same reference symbols are affixed, and overlapped explanation isomitted.

In the fourth variant example, the timing controller 206 itself withinthe casing 202 controls the imaging device 203 and the electricalstimulation device 205. By contrast to this, in this fifth variantexample, the timing controller 206 operates based upon a control signalfrom outside the living body.

In other words, as shown in FIG. 28, the capsule type medical device 220of this fifth variant example includes, within its casing 202, awireless transmission device 221 which wirelessly transmits by radiowaves the above described control signal between itself and an externaldevice not shown in the drawings, which is disposed externally to theliving body, and the timing controller 206 operates based upon thiscontrol signal.

The wireless transmission device 221 includes a wireless transmissioncircuit 222 and a signal transmission and reception antenna which is notshown in the figures, and it transmits the control signal which it hasreceived to the timing controller 206.

According to the capsule type medical device 220 which has this type ofstructure, by sending the control signal from the external device, it ispossible to control the operation of the imaging device 203 and of theelectrical stimulation device 205 easily and moreover accurately. Atthis time, the time period at which the control signal is sent may bethe same time period as the time period that the imaging circuit 210 orthe electrical stimulation circuit 11 is ON, or may be different. Inparticular, since no complicated circuitry and so on is required to beprovided for the timing controller 206, it is possible to anticipate areduction in the cost for the components, and it is also possible toanticipate a reduction in the size of the capsule type medical device201.

It should be understood that, in this fifth variant example, the imageswhich are taken images by the imaging device 203 may not be recorded inany memory 212; rather, it may be set so that they are transmitted viathe wireless transmission device 221 to the external device. By doingthis, it is possible to check the state of health of the person who isthe subject of investigation with the external device quickly.Furthermore, this example is not limited to the use of radio waves; itwould also be possible to control the timing controller 206 by someother type of control signal, such as by a magnetic field or the like.

Next, a sixth variant example of the first embodiment of the capsuletype medical device system of the present invention will be explained indetail with reference to the drawings. It should be understood that, tostructural elements which are the same as in the fifth variant example,the same reference symbols are affixed, and overlapped explanation isomitted.

In the fifth variant example, upon receipt of a control signal from theexternal device, the timing controller 206 within the casing 202operated at a different operational timing from the imaging device 203and the electrical stimulation device 205. By contrast to this, in thissixth variant example, the timing controller 206 is caused to operatesimultaneously with the imaging device 203 and the electricalstimulation device 205, and takes images of the living body tissue inthe state in which it is being held in position at the location which istaken images. In other words, as shown in FIG. 29, the capsule typemedical device 230 of this sixth variant example has, in addition to theelectrodes 204 which are provided at its one end, furthermore,electrodes 231 which are provided as a pair at the other end of thecasing 202, so as to sandwich the axial line of the casing 202.Furthermore, as shown in FIG. 30, the pair of electrodes 204 at the oneend of the casing are disposed in positions which are rotated, withrespect to the pair of electrodes 231 at the other end thereof, byapproximately 90° around the axial line as a central axis. It should beunderstood that the electrodes 231 at this other end of the casing aretransparent electrodes, just like the electrodes 204 at the one end ofthe casing. Furthermore, as described above, the timing controller 206operates at the same timing, as do the imaging device 203 and theelectrical stimulation device 205.

Since, according to the capsule type medical device 230 which isstructured in this manner, the electrodes 204 at the one end or theelectrodes 231 at the other end are positioned towards the front ortowards the back in the direction of progress, therefore, when anelectrical stimulus is applied to the living body tissue, the livingbody tissue shrinks so as to block the forward or reverse direction ofthe casing 202. Therefore, the capsule type medical device 201 does notmove in either the forward or the backward direction, and comes to be inthe state of staying in the same position. In other words, the livingbody tissue operates to close the lumen at the positions before andafter the casing 202, and comes to be in the state of moving in closelyso as to adhere closely to the outer surface of the casing 202.

The timing controller 206 causes the imaging device 203 to operate atthe same time, thus performing images of the living body tissue whichhas shifted and moved in closely so as to adhere closely to the outersurface of the casing 202. Accordingly, the imaging device 203 canperform images in the state in which the location which it is desired totake images has stopped, and in the state in which the living bodytissue is close up, so that it is possible for it to obtain good images,with which there is no blurring. In particular, since the image isperformed in a state in which the distance between the imaging device203 and the living body tissue is kept constant, for example, an imageis performed while eliminating the influences of loss of dark detail andwhite-out and the like. Furthermore, it is easy to see any lesion in thesmall intestine or the like, since the image is performed in a state inwhich the folded living body tissue is stretched out.

Yet further, since the electrodes 204 at the one end and the electrodes231 at the other end are offset by being rotated about 90°, taking theaxial line as a center line, therefore, when applying an electricalstimulus to the living body tissue, it is possible to apply theelectrical stimulus with good efficiency to the living body tissue whilealleviating their mutual influence. Accordingly, it is possible to causethe shrinkage operation to be performed upon the living body tissue morereliably.

It should be understood that, with this sixth variant example, theimaging element of the imaging device 203 may also be provided on theside surface of the casing 202, so as to be positioned between theelectrodes 204 at the one end and the electrodes 231 at the other end.By doing this, it is possible to take images of the living body tissuemore appropriately.

Next, a seventh variant example of the first embodiment of the capsuletype medical device system of the present invention will be explained indetail with reference to the drawings. It should be understood that, tostructural elements which are the same as in the fifth variant example,the same reference symbols are affixed, and overlapped explanation isomitted.

In the fifth variant example, the timing controller 206 within thecasing 202 caused the imaging device 203 and the electrical stimulationdevice 205 to operate at different operational timings, upon receipt ofa control signal from the external device. By contrast to this, in thisseventh variant example, after having operated the electricalstimulation device 205, the timing controller 206 operates the imagingdevice 203 after a predetermined time interval has elapsed.

As shown in FIG. 31, in this seventh variant example, after havingapplied an electrical stimulus to the living body tissue with theelectrical stimulation device 203, the timing controller 206 causes theimaging device 205 to operate after a predetermined time interval haselapsed, in other words after the capsule has shifted along thedirection of progress or backwards against the direction of progress.Accordingly, it is possible to obtain a desirable image without anyblurring or the like, since the image is performed after performingshifting via the operation of shrinking the living body tissue. Inparticular, by adjusting the predetermined time period, it is possibleto perform images in a state in which the living body tissue which isshrunk down has returned to its normal state, in other words, with thelumen, which had been blocked up, again having opened up.

It should be understood that, in this embodiment, it would also beacceptable to provide the electrodes at both ends of the casing 202, asin the above described sixth variant example. Furthermore, with thesixth variant example and the seventh variant example, it would beacceptable not to provide any wireless transmission device, and not toperform any wireless transmission with any external device, just as inthe fourth variant example. Yet further, in the fourth variant example,it would be acceptable to provide the electrodes at both ends of thecasing, just as in the sixth variant example.

Next, a second embodiment of the capsule type medical device system ofthe present invention will be explained with reference to FIG. 32. Itshould be understood that, to structural elements which have alreadybeen explained for the first embodiment, the same reference symbols areaffixed, and explanation thereof is omitted.

In this second embodiment, the various internal organs of the patientare observed from the ingestion of the capsule type medical device bymouth until it is excreted. By contrast to this, with the firstembodiment, as shown in FIG. 33, the capsule type medical device 2 isingested from the anus, and performs observation within the colon. Atthis time, it is ingested into the living body with the imaging elementfacing forwards. Upon ingestion, the capsule type medical device 2transmits the images of the colon which have been taken images by theimaging element 20 to the external device 3. Upon receipt thereof, theposition detection circuit 4 of the external device 3 detects that thecapsule type medical device 2 is positioned within the colon, and thecontrol section 33 transmits a control signal to the capsule typemedical device 2 to expand the balloon 13 and to apply an electricalstimulus. Upon receipt of this control signal, the control section 6 ofthe capsule type medical device 2 causes the expansion and shrinkagemechanism 22 to operate, thus causing the balloon 13 to expand, and alsoapplies an electrical stimulus to the living body tissue (the intestinaltract) by transmitting an electric current to the electrodes 5 from thecurrent generation circuit 23. At this time, the current generationcircuit 23 applies the electrical stimulus by supplying electric currentto the electrodes 5 at the other end of the capsule.

The living body tissue which has received this electrical stimulusperforms local shrinkage at the other end of the casing 10. Therefore,the capsule type medical device 2 performs images of the interior of thecolon with the imaging element 20 while shifting within the colon so asto move backwards, from the anus towards the small intestine. When itarrives at the caecum, the control section 33 of the external device 3sends a control signal to the capsule type medical device 2 to shrinkdown the balloon 13 and to stop the electrical stimulation.

Upon receipt of this signal, as shown in FIG. 32, the control section 6of the capsule type medical device 2, along with causing the expansionand shrinkage mechanism 22 to operate and thus causing the balloon 13 toshrink, also stops the electric current which is being supplied to theelectrodes 5, thus stopping the electrical stimulation. After this, thecapsule type medical device 2 is excreted naturally. At this time itsexcretability is enhanced, since the balloon 13 is shrunk down.

According to this type of embodiment, it is possible to perform drivingonly within the colon, of which observation is required, so that it ispossible to perform the observation more efficiently.

Furthermore, with the above described second embodiment, it is arrangedthat, when the capsule has arrived at the caecum, along with causing theballoon 13 to shrink down, the electrical stimulation is also stopped;but this is not to be considered as being limitative: for example, asshown in FIG. 33, it would also be acceptable to arrange matters sothat, when the capsule has arrived at the caecum, the electricalstimulation from the electrodes 5 on the other end of the capsule ischanged around for electrical stimulation from the electrodes 5 on theother end of the capsule. By doing this, it would be possible to causethe capsule type medical device 2, which had arrived at the caecum, tobe shifted back towards the anus again due to electrical stimulation. Itwould be acceptable to arrange, when the capsule arrived at the anus,along with shrinking down the balloon 13, also to stop the electricalstimulation. By doing this, it would be possible to take images of theinterior of the colon twice, while going up and while returning down, sothat it would be possible to perform more accurate observation and toreduce oversights and the like. Furthermore, it would be possible tocause excretion at an early stage, since it would be possible to inducemovement downwards to the anus.

It should be understood that although, in the above describedembodiment, the electrodes are provided respectively at the one end andat the other end of the casing with respect to its axial direction, thisshould not be considered as being limitative; it would be acceptable foreither one of these, only, to be provided; or, alternatively, aplurality could be provided. Furthermore although, in the abovedescribed embodiments, the electrodes are made as being provided uponthe outer surface of the casing or upon the outer surface of theballoon, a structure would also be acceptable in which the electrodesare disposed in the vicinity of the outer surface of the casing, withthe electrodes being covered over by an outer surface member which ismade from a material which has high electrical conductivity. In thiscase, in order to prevent short circuiting from the plus poles to theminus poles over the outer surface of the casing, an insulating stateshould be established between the material which covers the positivepoles and the material which covers the negative poles. By doing this,even if the electrodes are shaped to be very small, it is possible toperform electrical stimulation over a wide range of living body tissuevia the members upon the outer surface of the casing.

Furthermore, it would also be acceptable to impart the functions withwhich the control section of the external device is equipped to thecontrol section of the capsule type medical device. By doing this, itwould be possible to change the wireless transmission between thecapsule type medical device and the external device into one waycommunication(of in-vivo information) from the capsule type medicaldevice to the external device.

Furthermore, it would also be acceptable to provide the recordingdevice, not to the external device, but rather within the capsule typemedical device. In other words, it would be acceptable to embody thepresent invention as the capsule type medical device shown in FIG. 34.Along with this capsule type medical device 70 including a recordingdevice 32 within its casing 10, the control section 71 also includes acurrent generation circuit 23 and a position detection circuit 4.According to this capsule type medical device 70, when it is shiftingwithin the living body, its own position is detected by the positiondetection circuit 4, while it is recording images which have been takenimages by the imaging element 20, which are in-vivo information, in therecording device 32; and it is possible for the control section 71 tocontrol the current generation circuit 23 according to the site at whichit has arrived, so as to apply electrical stimulation. Accordingly, theoperation is very simple and convenient, since the person who is thesubject of investigation is not required to fit any external device.

It should be understood that, with this capsule type medical device aswell, in the same manner as with the capsule type medical device systemsdescribed above, it would be acceptable also to provide a pH sensor or aballoon as well.

Furthermore although, in the above described embodiments, a positiondetection device is provided for detecting the position of the capsuletype medical device, it would also be acceptable, as shown in FIG. 35,for the position detection device to include a decision circuit notshown in the figure which is provided to the control section, and adecision device which includes a timer (a setting section) not shown inthe figures, in which there is set in advance a parameter such as thetime period which is required until the capsule arrives at the targetsite within the living body or the like.

This timer is set in advance to the time period from when the capsule isingested into the living body until it arrives at a specified site. Ifthis capsule type medical device is applied to the above describedsecond embodiment, along with being able to decide, according to thetime period of the timer, from when it is ingested into the living bodyvia the anus to when it arrives at the caecum, it is also possiblefurther to decide according to the time period of the timer, from whenit is at the caecum to when it arrives back at the anus. According tothe site within the living body which has been decided upon by thedecision device, the control section may be set so as to performexpansion and shrinkage of the balloon, and performance of electricalstimulation.

It should be understood that the parameter is not limited to being aperiod of time; for example, as shown in FIG. 36, it would be acceptablefor it to be the amount of electrical stimulation such as the number ofpulses or the like which have been generated by the electrodes, and tomake the decision as to the target site based upon the number of pulses.In this case, it would be acceptable to set the current generationcircuit so as to supply electrical power in the form of pulses to theelectrodes, to store the number of pulses which are generated in thememory, and to make the decision and to stop the generation of pulsesand so on when this number has arrived at a number which is set inadvance.

It should be understood that the amount of electrical stimulation maynot only be the number of pulses; it would be acceptable for it to bethe sum of the widths of the pulses, the distribution of the pulsestrength, or the integrated value of the electric current which has beengenerated at the electrodes.

Furthermore, it would also be acceptable to utilize the features of anyone, or of any combination, of the first variant example through theseventh variant example of the first embodiment, with the secondembodiment.

Although, in the above, preferred embodiments of the present inventionhave been explained, the present invention is not to be considered asbeing limited to these embodiments described above. It would be possibleto make various additions, omissions, substitutions, and other changes,within a range in which the gist of the present invention is notdeparted from. The present invention is not to be considered as beinglimited by the preceding explanations; rather, it should be limited onlyby the range of the appended claims.

1. A capsule type medical device system which comprises a capsule typemedical device which can be ingested to within the living body, furthercomprising: a region determination device which determines a bodilyregion at which the capsule type medical device is located based onreferencing information set in advance; an electrode which is providedon the capsule type medical device, and which applies an electricalstimulus to living body tissue; and a control device which is providedon the capsule type medical device, and which controls an electriccurrent which flows to the electrode based on information of the bodilyregion determined by the region determination device; a second detectiondevice which is provided on the capsule type medical device, and whichdetects in-vivo information within the living body; wherein the regiondetermination device determines the bodily region at which the capsuletype medical device is located by comparing the in-vivo informationdetected by the second detection device with the referencing informationset in advance; wherein the second detection device comprises anacquisition device which acquires the in-vivo information; wherein theregion determination device determines an orientation of the capsuletype medical device within the body based on the in-vivo informationwhich is acquired by the acquisition device; and wherein the controldevice controls the electric current which flows in the electrode basedon the orientation of the capsule type medical device.
 2. A capsule typemedical device system according to claim 1, further comprising: astorage device which stores the in-vivo information.
 3. A capsule typemedical device system according to claim 1, further comprising: anelectrical stimulation device which comprises a plurality of theelectrodes; an electrode selection device which selects an electrodefrom among the plurality of electrodes, to apply an electrical stimulus;a contact detection device which electrically detects that the electrodeis in contact with the living body tissue; and a control section whichcontrols the electrical stimulation device, electrode selection device,and contact detection device.
 4. A capsule type medical device systemaccording to claim 3, wherein the electrical stimulation devicecomprises: one electrodes which are connected to the high electricalpotential side, and the other electrodes which are connected to the lowelectrical potential side, the electrode selection device comprises: afirst switching device which selects at least one electrode from amongthe one electrodes and connects it electrically to a supply source ofelectrical current; and a second switching device which selects at leastone electrode from among the other electrodes.
 5. A capsule type medicaldevice system according to claim 4, wherein the one electrode and theother electrode are each disposed at equal intervals around the outerperiphery of a cross section which is roughly orthogonal to an axialline which extends along the longitudinal direction of the casing of thecapsule type medical device.
 6. A capsule type medical device systemaccording to claim 4, wherein the one electrode and the other electrodeare disposed in multiple steps along the outer surface of the casing ofthe capsule type medical device, between from one end of the casing inits longitudinal direction to the other end thereof.
 7. A capsule typemedical device system according to claim 6, wherein a projecting portionwhich includes an inclined portion which slopes with respect to theaxial line along the longitudinal direction of the casing of the capsuletype medical device is provided, and the one electrode and the otherelectrode are provided upon the inclined surface.
 8. A capsule typemedical device system according to claim 7, wherein the inclined portioncomprises a portion which inclines towards a one end of the longitudinaldirection of the casing of the capsule type medical device, and aportion which inclines towards the other end of the longitudinaldirection of the casing, and at least one group of the one electrode andthe other electrode are disposed in respective portions of the inclinedportion.
 9. A capsule type medical device system according to claim 3,wherein the contact detection device is a force detection device.
 10. Acapsule type medical device system according to claim 9, wherein theforce detection device is strain gauges which are equipped to theelectrodes which are connected to the high electrical potential side andthe electrodes which are connected to the low electrical potential side.11. A capsule type medical device system according to claim 3, whereinthe contact detection device is a device which measures the impedancebetween the electrode which is connected to the high electricalpotential side and the electrode which is connected to the lowelectrical potential side.
 12. A capsule type medical device systemaccording to claim 3, wherein the electrical stimulation devicecomprises: a waveform generator which generates a predetermined voltagewaveform; a conversion circuit which converts the voltage waveform toelectric current; a limitation circuit which is used for adjusting theelectric current which flows to the electrode; and an electric currentsensor which detects the electric current, wherein the control sectionadjusts the gain of the limitation circuit according to the output ofthe electric current sensor.
 13. A capsule type medical device systemaccording to claim 12, wherein the electrical stimulation devicecomprises a resistor between the limitation circuit and the electrode.14. A capsule type medical device system according to claim 12, whereinthe electrical stimulation device generates an electric current waveformwhich is a continuous curve of roughly square form.
 15. A capsule typemedical device system according to claim 12, wherein the electricalstimulation device generates an electric current waveform which is astep shaped triangular wave.
 16. The capsule type medical device systemaccording to claim 1, further comprising a first detection device whichdetects positional information regarding a position at which the capsuletype medical device is located, wherein the region determination devicedetermines the bodily region at which the capsule type medical device islocated by comparing the positional information detected by the firstdetection device with the referencing information set in advance. 17.The capsule type medical device system according to claim 1, wherein thesecond detection device comprises an acquisition device which acquiresthe in-vivo information, and the region determination device determinesthe position of the capsule type medical device within the living body,by using the in-vivo information which is acquired by the acquisitiondevice.
 18. The capsule type medical device system according to claim17, wherein the acquisition device is an imaging device which takesimages of the inside of the living body, and the region determinationdevice determines the position of the capsule type medical device withinthe living body, based upon an image which is taken by the imagingdevice.
 19. The capsule type medical device system according to claim18, wherein the region determination device compares at least onecharacteristic of brightness, color, frequency distribution and bodilysurface condition in the image with the referencing information set inadvance, and thereby the region determination device determines thebodily region at which the capsule type medical device is located. 20.The capsule type medical device system according to claim 1, wherein thecapsule type medical device comprises a balloon which can be expanded soas to closely contact to living body tissue or can be shrunk down, theelectrode is provided upon the outer surface of the balloon, and thecontrol device expands or shrinks down the balloon, based upon theinformation of the bodily region.
 21. The capsule type medical devicesystem according to claim 17, wherein the acquisition device is a pHsensor which measures the pH value within the living body, and theregion determination device determines the position of the capsule typemedical device within the living body, based upon the pH value.
 22. Thecapsule type medical device system according to claim 1, wherein thecapsule type medical device is provided with a plurality of theelectrodes, and the control device controls the electric current whichflows in the plurality of electrodes, based upon the information of thebodily region.
 23. The capsule type medical device system according toclaim 1, further comprising at least one of a body sampling sectionwhich samples the living body tissue and a body treatment section whichtreats the living body.
 24. The capsule type medical device systemaccording to claim 1, wherein the electrode forms part of an outersurface of the capsule type medical device.
 25. An operating method ofcapsule type medical device, comprising: determining a bodily region atwhich the capsule type medical device is located based on referencinginformation set in advance; generating a control signal based oninformation of the bodily region, controlling the electric current whichflows to an electrode provided on the capsule type medical device usingthe generated control signal; detecting in-vivo information within theliving body with a second detection device which is provided on thecapsule type medical device, wherein the second detection devicecomprises an acquisition device which acquires the in-vivo information;wherein the determining of the bodily region at which the capsule typemedical device is located comprises comparing the in-vivo informationdetected by the second detection device with the referencing informationset in advance; determining an orientation of the capsule type medicaldevice within the body based on the in-vivo information which isacquired by the acquisition device; and wherein the controllingcomprises controlling the electric current which flows in the electrodebased on the orientation of the capsule type medical device.
 26. Theoperating method of capsule type medical device according to claim 25,wherein the in-vivo information comprises at least one characteristic ofbrightness, color, frequency distribution and surface condition of thebody.
 27. An operating method of capsule type medical device,comprising: determining a bodily region at which the capsule typemedical device is located based on referencing information set inadvance; generating a control signal based on information of the bodilyregion, controlling the electric current which flows to an electrodeprovided on the capsule type medical device using the generated controlsignal; detecting in-vivo information within the living body byacquiring the in-vivo information; wherein the determining of the bodilyregion at which the capsule type medical device is located comprisescomparing the acquired in-vivo information with the referencinginformation set in advance; determining an orientation of the capsuletype medical device within the body based on the acquired in-vivoinformation; and wherein the controlling comprises controlling theelectric current which flows in the electrode based on the orientationof the capsule type medical device.
 28. The operating method of capsuletype medical device according to claim 27, wherein the in-vivoinformation comprises at least one characteristic of brightness, color,frequency distribution and surface condition of the body.